Selectable multiband isolation of single pole double throw switch using transmission line stub resonator for WiMAX and LTE applications
2016; Institution of Engineering and Technology; Volume: 11; Issue: 6 Linguagem: Inglês
10.1049/iet-map.2016.0868
ISSN1751-8733
AutoresA. M. Zobilah, Zahriladha Zakaria, N. A. Shairi,
Tópico(s)Full-Duplex Wireless Communications
ResumoIET Microwaves, Antennas & PropagationVolume 11, Issue 6 p. 844-851 Research ArticleFree Access Selectable multiband isolation of single pole double throw switch using transmission line stub resonator for WiMAX and LTE applications Abdullah M. Zobilah, Corresponding Author Abdullah M. Zobilah zobilah12@hotmail.com Centre for Telecommunication Research & Innovation (CeTRI) Faculty of Electronics and Computer Engineering, UniversitiTeknikal Malaysia Melaka (UTeM), Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, MalaysiaSearch for more papers by this authorZahriladha Zakaria, Zahriladha Zakaria Centre for Telecommunication Research & Innovation (CeTRI) Faculty of Electronics and Computer Engineering, UniversitiTeknikal Malaysia Melaka (UTeM), Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, MalaysiaSearch for more papers by this authorNoor Azwan Shairi, Noor Azwan Shairi Centre for Telecommunication Research & Innovation (CeTRI) Faculty of Electronics and Computer Engineering, UniversitiTeknikal Malaysia Melaka (UTeM), Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, MalaysiaSearch for more papers by this author Abdullah M. Zobilah, Corresponding Author Abdullah M. Zobilah zobilah12@hotmail.com Centre for Telecommunication Research & Innovation (CeTRI) Faculty of Electronics and Computer Engineering, UniversitiTeknikal Malaysia Melaka (UTeM), Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, MalaysiaSearch for more papers by this authorZahriladha Zakaria, Zahriladha Zakaria Centre for Telecommunication Research & Innovation (CeTRI) Faculty of Electronics and Computer Engineering, UniversitiTeknikal Malaysia Melaka (UTeM), Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, MalaysiaSearch for more papers by this authorNoor Azwan Shairi, Noor Azwan Shairi Centre for Telecommunication Research & Innovation (CeTRI) Faculty of Electronics and Computer Engineering, UniversitiTeknikal Malaysia Melaka (UTeM), Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, MalaysiaSearch for more papers by this author First published: 15 March 2017 https://doi.org/10.1049/iet-map.2016.0868Citations: 4AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Abstract A selectable multiband isolation of single pole double throw (SPDT) switch with switchable transmission line stub resonators for applications of WiMAX and LTE in 2.3 and 3.5 GHz bands is presented. Two SPDT switches are presented. (Design 2) either allows selecting only one band while unselecting the other or selecting both of them. However, (Design 1) does not allow so. The transmission line stub resonator used in this design is an open stub resonator with quarter wave of the electrical length. By using a simple mathematical model, the theory of the transmission line stub resonator was discussed where it can be cascaded and resonated at centre frequencies of 2.3 and 3.5 GHz. Moreover, the cascaded transmission line stub resonators can be reconfigured between all-pass and band-stop responses using discrete PIN diodes. The key advantage of the proposed SPDT with switchable transmission line stub resonators is a multiband high isolation with a minimum number of PIN diodes. Therefore, the simulated and measured results showed the followings: 10 dB of return loss and >30 dB of multiband isolation in 2.3 and 3.5 GHz bands. 1 Introduction The rapid development in wireless communication systems led to switchable/selectable radio designs which are highly popular due to its ability to operate with different frequencies using single hardware. For instance, switchable slot antenna has been designed to support the entire UWB operation frequency, and at the same time, it created a dual band notch to notch the frequency bands of interference between UWB with WLAN, C-band, and WiMAX systems [[1]]. Furthermore, a dual band switchable band-pass filter was proposed in [[2]] with the ability to switch between passband, low-band and high-band by controlling the bias voltage of PIN diodes. In [[3]], a frequency switchable T-slot antenna was designed to support diverse applications such as WiMAX, C-band, X-band and fixed satellite communication systems by controlling the PIN diode states (ON and OFF states). Moreover, [[4]] introduced single pole double throw (SPDT) switchable band-pass filter design to operate at narrow band applications. This design combined SPDT with two filters and it has the ability to ON one filter and OFF the other by controlling the PIN diodes, switching elements. For multiband wireless communications, the development of multiband sub-components (e.g. amplifiers, filters, switches and antennas) are highly desired, and they were developed to support several RF front-end systems [[5]–[7]]. Meanwhile, SPDT switch (which is a part of RF switches) is ordinarily used in RF front-end system to switch between up-link (transmitter mode) and down-link (receiver mode) [[8]–[11]] or, in general, to switch between two different signal paths [[12]]. From the literature, SPDT switches could be designed and used in applications such as time division duplex (e.g. WiMAX and LTE) [[13], [14]], X-band applications [[15]], low-frequency applications [[10]], communication and radar applications [[9]], millimeter-wave applications and high-power applications [[11]] such as base statins which is the target for the proposed design. SPDT switch topologies can be divided into two main topologies: asymmetrical [[8], [16]–[18]] and symmetrical [[10], [11]]. Both are used to perform switching for high-power applications [[11], [18]] but the latter produces higher isolation than the former. On the other hand, there are three popular configurations for SPDTs: series [[19]], shunt [[11]] and series-shunt configurations [[10]]. However, the third configuration is the best choice when high isolation and high-power applications of wireless communication such as base stations, military and satellite communication are targeted, as reported in [[20], [21]]. RF switch (such as SPDT switch) elements can be categorised as micro-electro-mechanicals (MEMs) [[22]] or solid state elements such as PIN diode [[9], [11]] and field effect transistor [[10], [23]]. However, MEMs switches are not suitable for high-power applications due to their limited power capabilities [[24]]. Moreover, they have not been widely used in RF and microwave applications since the PIN diode was developed and commercialised [[20]]. Additionally, solid-state switches, such as PIN diode switch, show more reliability due to faster switching time and they accomplish a longer lifetime in comparison to MEMs technology. Consequently, if the fast switching time, long lifetime and high-power applications are the key performance requirements, the most popular switching element used is PIN diode [[20], [25]]. In SPDT switch design, high isolation plays an important role in preventing unwanted leakage signal [[26]]. Furthermore, to increase the switch's isolation, researchers have reported different techniques such as series PIN diode with compensation parasitic capacitance [[27]], a lumped λ/4 transformer [[8]], hollow waveguide [[12]], resistive bias network [[10]], and other techniques reported in [[28]]. However, for the solution of discrete circuit design using standard discrete PIN diode packages, there are trade-offs in these high isolation techniques such as increasing the overall circuit size, a higher number of PIN diodes and a limited choice of lumped component values. On the other hand, for discrete RF switches such as [[11]], it is quite hard to get high isolation (>30 dB) when using only discrete PIN diodes and usually multiple cascaded PIN diodes are required for high isolation performance. Therefore, this paper proposes a selectable multiband isolation of SPDT switch design with switchable transmission line stub resonators for applications of WiMAX and LTE in 2.3 and 3.5 GHz bands. Discrete PIN diodes were used in the proposed SPDT switch due to its advantage of higher power levels used in wireless communication systems. Generally, resonators were used to build up several RF and microwave circuit designs such as antennas [[20]], amplifier [[21]], filter [[22]], switch [[29]] and microwave absorber [[24]]. Thus, by using this technique (resonator) and together with discrete PIN diodes in SPDT switch design, the key advantage is a multiband high isolation with minimum number of PIN diodes when compared with conventional multiple cascaded PIN diodes. 2 Switchable transmission line stub resonators In this section, we discuss mathematical modelling for the isolation of multiband SPDT switch with transmission line stub resonator in a simple analysis form. Fig. 1 shows two-port network of series-shunt PIN diode with transmission line open stub resonators. From Fig. 1, we analysed the ABCD matrix of two port network, thus taking into account that shunt PIN diodes are switched ON, while series PIN diode is switched OFF. Thus, (1) where Z = Rr + jXr is known as the reference impedance of the PIN diode. Then we find the ABCD matrix for resonators (S1) and (S2) (2) (3) where ZO is known as the impedance of the resonator. Then, to determine the isolation at 2.3 GHz, we replace ZO by ZS2. Thus (4) (5) (6) Fig. 1Open in figure viewerPowerPoint Two-port network of series-shunt PIN diode with open stub resonators Assume (length of the quarter wave), ZS2 = ZO = 1. Therefore, (7) Convert to decibel (8) To determine the isolation at 3.5 GHz, we replace ZO by ZS1. Thus (9) (10) Assume θ = π/2 (length of the quarter wave), ZS1 = 1. Therefore, (11) Convert to decibel (12) Theoretically, it is clearly observed that infinite isolation S21 can be achieved if ZS = 1 and θ = π/2. From (8) and (12), an ideal infinite attenuation (notch) was produced if the electrical length of the transmission line stub was a quarter wave (λ/4). This attenuation characteristic was used to produce multiband high isolation in SPDT switch. 3 Fixed SPDT switch design (Design 1) Fig. 2 shows the diagram of multiband isolation fixed SPDT switch. Actually, four open stub resonators (S1, S2, S3 and S4) are used to achieve high isolation for WiMAX and LTE applications. Resonators S1 and S4 are assigned to resonate at 3.5 GHz, while S2 and S3 are assigned to resonate at 2.3 GHz. Quarter wavelength (λ/4) is placed in between S1 and S2 as well as between S3 and S4, to transform from low impedance of the resonators to high impedance in the microstrip line. Fig. 2Open in figure viewerPowerPoint Circuit diagram of fixed multiband isolation SPDT switch, Design 1 (transmitter mode) Generally, this circuit has been built to switch between the transmitter (Tx) mode and receiver (Rx) mode. To do so, series PIN diodes (D5 and D6) and shunt PIN diodes (D1–D4) are used. These PIN diodes are controlled by biasing circuits (Vbias 1 and Vbias 2). In this section, we will discuss the circuit operation during the transmitter (Tx) mode only, due to the symmetrically construction of the SPDT switch circuit. Therefore, during the transmitter (Tx) mode process, as illustrated in Fig. 2, RF signals propagate from transmitter (Tx) to Antenna. In this case, series PIN diode D5 is turned ON, while shunt PIN diodes, in the transmitter (Tx) arm, D1 and D2 are turned OFF with voltage control, 5 V. So, transmission line open stub resonators S1 and S2 create all-pass response. On the other hand, series PIN diode D6 is turned OFF, while shunt PIN diodes, in receiver (Rx) arm, D3 and D4 are turned ON with voltage control, −5 V. So, transmission line open stub resonators S3 and S4 create band stop response. Obviously, in this process, the created band stop response in the receiver (Rx) arm is the most responsible of the isolation between transmitter (Tx) and receiver (Rx). Table 1 presents a summary of the process in receiver (Rx) and transmitter (Tx) modes of fixed multiband isolation SPDT switch using transmission line open stub resonators for WiMAX and LTE applications at 2.3 and 3.5 GHz bands. Table 1. Summarisation of the process in receiver and transmitter modes of fixed multiband isolation SPDT switch Receiver mode Transmitter mode Vbias1 −5 V +5 V Vbias2 +5 V −5 V series PIN diode (D5) OFF state ON state series PIN diode (D6) ON state OFF state transmission line stub resonators (S1, S2) band-stop response all-pass response transmission line stub resonators (S3, S4) all-pass response band-stop response 4 Selectable SPDT switch (Design 2) Fig. 3 presents the diagram of selectable multiband isolation SPDT switch. In fact, this design is modified based on the previous design (Design 1). More capacitors and biasing circuits (Vbias 2, 3, 4 and 5) are added to allow selecting operation frequencies in three different cases; 2.3 GHz only (Case 1), 3.5 GHz only (Case 2) or both 2.3 and 3.5 GHz (Case 3). In general, this switch circuit is built to switch between the transmitter (Tx) mode and receiver (Rx) mode. To do so, series PIN diodes (D5 and D6) and shunt PIN diodes (D1–D4) are used. These PIN diodes are controlled by biasing circuits (Vbias 1–Vbias 6). For the DC block, C, the chosen value is 10 pF to achieve high-pass response. Fig. 3Open in figure viewerPowerPoint Circuit diagram of selectable multiband isolation SPDT, Design 2 (transmitter mode) During the transmitter mode process, RF signals propagate from transmitter (Tx) to Antenna, as can be seen in Fig. 3. We have mentioned that in this design there are three different cases. In the first case (selecting 2.3 GHz band only), Vbias 1 and Vbias 6 must be deactivated. Then, in transmitter (Tx) arm, series PIN diode, D5 is turned ON, while shunt PIN diode, D2 is turned OFF with voltage control, 5 V. So, the transmission line open stub resonator S2 creates an all-pass response. On the other hand, in receiver (Rx) arm, series PIN diode D6 is turned OFF, while shunt PIN diode, D3 is turned ON with voltage control, −5 V. So, the transmission line open stub resonator S3 creates a band-stop response. In the second case (selecting 3.5 GHz band only), Vbias2 and Vbias5 must be deactivated. Then, in the transmitter (Tx) arm, series PIN diode, D5 is turned ON, while shunt PIN diode, D1 is turned OFF with voltage control, 5 V. So, the transmission line open stub resonator S1 creates an all-pass response. In contrast, in receiver (Rx) arm, series PIN diode D6 is turned OFF, while shunt PIN diode, D4 is turned ON with voltage control, −5 V. So, the transmission line open stub resonator S4 creates a band-stop response. In the third case (selecting both 2.3 3.5 GHz bands), all biasing circuits must be activated. Then, in the transmitter (Tx) arm, series PIN diode, D5 is turned ON, while shunt PIN diodes, D1 and D2 are turned OFF with voltage control, 5 V. So, transmission line open stub resonators, S1 and S2 create an all-pass response. On the other hand, in the receiver (Rx) arm, series PIN diode D6 is turned OFF, while shunt PIN diodes, D3 and D4 are turned ON with voltage control, −5 V. So, transmission line open stub resonators S3 and S4 create a band-stop response. Obviously, in all cases, the created band-stop response in the receiver (Rx) arm is most responsible for the isolation between the transmitter (Tx) and the receiver (Rx). Table 2 presents a summary of the process in the receiver and transmitter modes of selectable multiband isolation SPDT switch using transmission line open stub resonators for WiMAX and LTE applications at 2.3 and 3.5 GHz bands. Table 2. Summarisation of the process in receiver and transmitter modes of selectable multiband isolation SPDT switch Receiver mode Transmitter mode Case 1 (select 2.3 GHz band) Vbias1 deactivated deactivated Vbias2 −5 V +5 V Vbias3 −5 V +5 V Vbias4 +5 V −5 V Vbias5 +5 V −5 V Vbias6 deactivated deactivated PIN diode (D5) OFF state ON state PIN diode (D6) ON state OFF state resonator (S1) no response no response resonator (S2) band-stop response all-pass response resonator (S3) all-pass response band-stop response resonator (S4) no response no response Case 2 (select 3.5 GHz band) Vbias1 −5 V +5 V Vbias2 deactivated deactivated Vbias3 −5 V +5 V Vbias4 +5 V −5 V Vbias5 deactivated deactivated Vbias6 +5 V −5 V PIN diode (D5) OFF state ON state PIN diode (D6) ON state OFF state resonator (S1) band-stop response all-pass response resonator (S2) no response no response resonator (S3) no response no response resonator (S4) all-pass response band-stop response Case 3 (select 2.3 and 3.5 GHz bands) Vbias1 −5 V +5 V Vbias2 −5 V +5 V Vbias3 −5 V +5 V Vbias4 +5 V −5 V Vbias5 +5 V −5 V Vbias6 +5 V −5 V PIN diode (D5) OFF state ON state PIN diode (D6) ON state OFF state resonator (S1) band-stop response all-pass response resonator (S2) bands-top response all-pass response resonator (S3) all-pass response band-stop response resonator (S4) all-pass response band-stop response Advanced design system (ADS) software was used for SPDTs, Designs 1 and 2, performance simulation and layout design. To build up the switch circuit, a microstrip model in ADS was used based on FR4 substrate with the following parameters; thickness = 1.6 mm and relative dielectric constant, εr = 4.7. PIN diodes (part number: BAP64-02) from NXP and the capacitors and inductors from Murata were used in the circuit design as well. For the DC block, C, the chosen value is 10 pF to achieve a high pass response. For the RF choke, L, the chosen value is 10 nH to block RF signals at 2.3 and 3.5 GHz. 5 Simulation and measurement results for SPDT switch (Design 1) Fig. 8a shows the prototype of fixed multiband isolation SPDT switch for WiMAX and LTE at 2.3 and 3.5 GHz. The layout's total area of the switch design is 29 mm × 52 mm. The dimensions of the transmission line stub resonators (S1, S2, S3 and S4) were as follows. For S1 and S4, the final dimension were W = 2.9 mm and l = 7 mm (at 3.5 GHz). However, for S2 and S3, the final dimension where W = 2.9 mm and l = 13.45 mm (at 2.3 GHz). During the simulation process, these final dimensions were determined together with the parasitic effect of the PIN diodes such as the effect of junction capacitance and series inductance. The simulation and measurement results were compared with each other in terms of the return loss, insertion loss and isolation, as shown in Fig. 4. As illustrated in Fig. 4a, the isolation performance (S13) of the fixed multiband isolation SPDT switch reached more than 30 dB at 2.3 and 3.5 GHz in simulation results as well as in the measurement result. In addition, it was found that >30 dB of isolation was obtained with only three PIN diodes in each arm; transmit arm and receive arm. By having >30 dB of isolation, the fixed SPDT switch can isolate >1 W/10 W of power leakage in the RF front-end system. However, the resonant frequency of isolation, 2.3 GHz (in measurement) shifted to a higher frequency (2.42 GHz) due to the passive/active component, tolerance of substrate as well as the fabrication process. Generally, the simulated isolation for WiMaX and LTE applications at 2.3 and 3.5 GHz were 46.5 and 41.2 dB, respectively. While the measured isolation for 2.3 and 3.5 GHz were 33.1 and 35.7 dB, respectively. Fig. 4Open in figure viewerPowerPoint Simulation and measurement results of SPDT switch (Design 1) (a) Isolation (S13), (b) Return loss (S11), (c) Insertion loss (S12) The simulation result and measurement result for the return loss (S11) and insertion loss (S12) for WiMAX application and LTE application are displayed in Figs. 4b and c, respectively. As seen in Fig. 4b, for 2.3 GHz, the return loss (S11) achieved 16.4 dB (in simulation) and 23.8 dB (in measurement). For 3.5 GHz, the return loss (S11) achieved 16.7 and 20.0 dB in simulation and in measurement, respectively. As indicated in Fig. 4c, the simulated insertion loss (S12) was 0.6 dB for 2.3 GHz and 0.7 dB for 3.5 GHz, while the measured insertion loss (S12) was 0.9 dB for 2.3 GHz and 1.7 dB for 3.5 GHz. The value of the resistors at the biasing circuit was 47 Ω, so the total current was limited to 87.0 mA during simulation and 80.0 mA during measurement. Table 3 summarises all the measured and simulated results of the fixed multiband isolation SPDT switch with transmission line stub resonators. Table 3. Performance summary of fixed multiband isolation SPDT switch with transmission line stub resonator (Design 1) Fixed SPDT switch Isolation (dB) Insertion loss, dB Return loss, dB 2.3 GHz band simulation 46.52 0.60 16.40 measurement 33.14 0.94 23.83 3.5 GHz band simulation 41.25 0.71 16.76 measurement 35.72 1.73 20.09 6 Simulation and measurement results for selectable SPDT switch (Design 2) The selectable multiband isolation SPDT switch for WiMAX and LTE applications at 2.3 and 3.5 GHz was fabricated and its isolation, return loss and insertion loss were validated experimentally using the Agilent Network Analyser (N5242A). Fig. 8b shows the prototype of the selectable multiband isolation SPDT switch. A parametric study was conducted and the optimised dimensions of the resonators (S1, S2, S3 and S4) were as follows: W1 = W4 = 2.9 mm, l1 = l4 = 7.35 mm, W2 = W3 = 2.9 and l2 = l3 = 13.6 mm. The total area of the prototype is 29 mm × 84 mm. The selectable multiband isolation SPDT switch can switch between transmitter mode and receiver mode in three different cases; Case 1 is to select 2.3 GHz only, Case 2 is to select 3.5 GHz only and Case 3 is to select both 2.3 and 3.5 GHz. The resistors value at the biasing circuit was 47 Ω. Therefore, the total current was limited to 87.0 mA during simulation and 80.0 mA during measurement. 6.1 Case 1: select 2.3 GHz band only As seen in Fig. 5, the simulation and measurement results show a good agreement. In Case 1, only 2.3 GHz band was selected (by voltage control) which can be applicable for WiMAX and LTE applications. To explain the results in details, both the measured and simulated isolation (S13) are >30 dB which can isolate >1 W/10 W of power leakage in the RF front-end system. The measured isolation between the transmitter and the receiver modes (S13) is 44.65 dB, while the simulated isolation is 44.50 dB, as presented in Fig. 5a. Fig. 5Open in figure viewerPowerPoint Simulation and measurement results of selectable multiband isolation SPDT switch (Case 1) (a) Isolation (S13), (b) Return loss (S11), (c) Insertion loss (S12) Figs. 5b and c compare the simulation and measurement results of the return loss (S11) and the insertion loss (S12), respectively. As can be indicated in Fig. 5b, the measurement result and simulation result of the return loss (S11) at 2.3 GHz (for WiMAX and LTE applications) both reach >10 dB, which is the minimum specification of the return loss. As can be seen in Fig. 5c, the simulated insertion loss (S12) is 1.1 dB, while the measured insertion loss (S12) is 1.2 dB. However, the slight difference between the simulation and measurement results is probably attributed to substrate tolerances, active or passive components and fabrication process. Table 4 summarises all simulation and measurement results of the multiband isolation SPDT switch with transmission line stub resonators (Case 1). Table 4. Performance summary of selectable SPDT switch with transmission line stub resonators (Case 1) Selectable SPDT switch Isolation, dB Return loss, dB Insertion loss, dB 2.3 GHz band simulation 44.50 12.00 1.16 measurement 44.65 16.06 1.24 3.5 GHz band simulation 17.77 18.37 1.15 measurement 18.00 22.28 1.41 6.2 Case 2: select 3.5 GHz band only The simulated and measurement results of the isolation between the transmitter and receiver were also compared to each other. As shown in Fig. 6a, there is a good agreement where the isolation performance reached >30 dB for the selected frequency, 3.5 GHz. However, the slight difference between measurement and simulation is probably due to substrate tolerance, fabrication and soldering processes. To analyse the switch circuit performances for WiMAX and LTE applications, the simulation and measurement results of the isolation, S13 (at 3.5 GHz) reached 43 and 35 dB, respectively, whereas the isolation at 2.3 GHz is only 17 dB (in simulation) and 14 dB (in measurement). Fig. 6Open in figure viewerPowerPoint Simulation and measurement results of selectable multiband isolation SPDT switch (Case 2) (a) Isolation (S13), (b) Return loss (S11), (c) Insertion loss (S12) The simulation and measurement results of the return loss, S11 for WiMAX and LTE applications at 2.3 and 3.5 GHz were compared to each other as shown in Fig. 6b. For 2.3 GHz band, the simulated and measured return loss, S11 are 11 and 14 dB, respectively, whereas for 3.5 GHz, the simulated return loss, S11 achieved 19 dB and the measured S11 achieved 18 dB. On the other hand, the result of the insertion loss S12 for the applications and operation frequencies, mentioned above, is illustrated in Fig. 6c. For 2.3 GHz band, the simulated insertion loss, S12 is 1.3 dB, while the measured is 1.4 dB. For 3.5 GHz band, the simulated insertion loss, S12 is 1.0 dB, whereas the measured is 1.4 dB. Table 5 summarises all simulation and measurement results of the multiband isolation SPDT switch with transmission line stub resonators (Case 2). Table 5. Performance summary of selectable SPDT switch with transmission line stub resonators (Case 2) Selectable SPDT switch Isolation, dB Return loss, dB Insertion loss, dB 2.3 GHz band simulation 17.49 11.60 1.31 measurement 14.27 14.59 1.4 3.5 GHz band simulation 43.77 19.17 1.01 measurement 35.80 18.44 1.43 6.3 Case 3: select 2.3 and 3.5 GHz bands The simulated and measurement results of isolation were compared to each other. In Fig. 7a, there is a good agreement where the isolation performance reached >30 dB for 3.5 GHz band. However, the slight difference between measurement and simulation, as shown in Fig. 7, is probably because of substrate tolerance, fabrication and soldering processes. For analysing the switch circuit performances for WiMAX and LTE applications, the simulation result of isolation, S13 is 43 dB (for 2.3 GHz) and 45 dB (for 3.5 GHz), while the measurement result is 42 dB (for 2.3 GHz) and 40 dB (for 3.5 GHz). Fig. 7Open in figure viewerPowerPoint Simulation and measurement results of selectable multiband isolation SPDT switch (Case 3) (a) Isolation (S13), (b) Return loss (S11), (c) Insertion loss (S12) Fig. 8Open in figure viewerPowerPoint The prototype of selectable and fixed multiband isolation (a) Design 1, (b) Design 2 The simulation and measurement results of the return loss, S11 for WiMAX and LTE applications at 2.3 and 3.5 GHz were also compared to each other as shown in Fig. 7b. For 2.3 GHz band, the simulated and measured return loss, S11 are 12 and 16 dB, respectively. However, for 3.5 GHz, the simulated return loss, S11 achieved 19 dB and the measured S11 achieved 21 dB. In contrast, the result of insertion loss S12 for the applications and operation frequencies, mentioned above, is illustrated in Fig. 7c. For 2.3 GHz band, the simulated insertion loss, S12 is 1.1 dB, while the measured is 1.3 dB. For 3.5 GHz band, the simulated insertion loss, S12 is 1.0 dB, while the measured is 1.3 dB. Table 6 summarises all simulation and measurement results of the selectable multiband isolation SPDT switch with transmission line stub resonators (Case 3). Table 6. Performance summary of selectable SPDT switch with transmission line stub resonators (Case 3) Selectable SPDT switch Isolation, dB Return loss, dB Insertion loss, dB 2.3 GHz band simulation 43.07 12.00 1.16 measurement 42.00 16.44 1.32 3.5 GHz band simulation 45.79 19.09 1.03 measurement 40.04 21.04 1.31 It was found that, in (Design 1), the isolation reached around 33 dB for 2.3 GHz and 35 dB for 3.5 GHz while in (Design 2), the isolation results were higher as they reached 42 dB for 2.3 GHz and 40 dB for 3.5 GHz. These were the measurement results, as the designs were fabricated to validate the simulation results. Only six PIN diodes were enough for each switch to get the mentioned high isolation performance due to the use of the transmission line stub resonators. However, (Design 2) allows selecting only one band and unselecting the other or selecting both of them, while (Design 1) does not do so. By having >30 dB of isolation, these two designs can be appropriate for high power of wireless communication and can isolate >1 W/10 W of power leakage in the RF front-end systems. Table 7 presents a comparison between the previous research works and this work. Table 7. Comparison between the previous research works and this work Works Technique Element App S13, dB Selectable this work switchable open stub resonator PIN diode WiMAX/LTE 44.6 yes [[8]] lumped λ/4 transformer PIN DIODE T/R 26 no [[11]] switchable open stub resonator PIN diode WiMAX/LTE 37 no [[15]] resonator PIN diode X-band 15–31 no [[27]] series PIN diode with compensation parasitic capacitance PIN diode radar (S-band) 19 no [[12]] hollow waveguide — W-band 16 no [[30]] HMSIW units — — 28.5 no 7 Conclusion A new SPDT switch with switchable transmission line stub resonators was successfully designed and validated at 2.3 and 3.5 GHz bands. Two SPDT switches were proposed. The results indicate that while (Design 2) allows selecting only one band and unselecting the other or selecting both of them (Design 1) does not allow this. The circuit operation of the cascaded switchable transmission line stub resonators was discussed where it could be reconfigured between all-pass and band-stop responses at 2.3 and 3.5 GHz. Then, it was applied in a multiband isolation of SPDT switch design where it was designed using series-shunt configuration. The two SPDT switches, Design 1 and Design 2, were successfully simulated in ADS software and fabricated on the FR4 board. As a result, the designs showed >30 dB isolation, 10 dB return loss in 2.3 and 3.5 GHz bands. Moreover, >30 dB of multiband isolation, in both designs, was obtained with only three discrete PIN diodes in each arm. This type of design is suitable for multiband RF front-end application such as in WiMAX and LTE. 8 Acknowledgments We thank the Centre for Telecommunication Research and Innovation, UniversitiTeknikal Malaysia Melaka for their encouragement to complete this research work. Also, we thank Centre for Research and Innovation Management for the financial support. 9 References [1]Badamchi, B., Nourinia, J., Ghobadi, C., et al.: 'Design of compact reconfigurable ultra-wideband slot antenna with switchable single/dual band notch functions', IET Microw. Antennas Propag., 2013, 8, (8), pp. 541– 548 [2]Chao, S., Kuo, C., Lin, W., et al.: 'A dual-band switchable bandpass filter using connected-coupling mechanisms'. Proc. 44th European Microwave Conf., 2014, pp. 941– 944 [3]Kumari, R., Kumar, M.: 'Frequency reconfigurable multi-band inverted t-slot antenna for wireless application'. Proc. Advances in Computing, Communications and Informatics (ICACCI, 2014 International Conf.), 2014, pp. 696– 699 [4]Chen, C., Wu, J., Lin, Y., et al.: 'Compact single-pole-double-throw switchable bandpass filter based on multicoupled line', IEEE Microw. Wirel. Components Lett., 2014, 24, (2), pp. 87– 89 [5]Wang, X., Ryu, H.: 'Design of multi-band receiver with pre-fft beamformer for wireless communications'. Proc. Advanced Communication Technology (ICACT), 2013 15th International Conf., January 2013, pp. 227– 232 [6]Lu, J.-H., Huang, B.-J.: 'Planar multi-band monopole antenna with l-shaped parasitic strip for wimax application', Electron. Lett., 2010, 46, (10), pp. 671– 672 [7]Zobilah, A.M.S., Shairi, N.A., Zakaria, Z., et al.: 'RF switches in wide-, broad-, and multi-band RF front-end of wireless communications : an overview', ARPN J. Eng. Appl. Sci., 2016, 11, (5), pp. 3244– 3248 [8]Ju, I., Schmid, R.L., Cho, M., et al.: 'Co-design of a SiGe BiCMOS x-band, asymmetric, low insertion loss, high power handling SPDT switch and an ultra low noise LNA for next-generation T/R modules'. Proc. Microwave Symp. (IMS), 2016 IEEE MTT-S International, May 2016, pp. 1– 4 [9]Naidu, P.V., Malhotra, A.: 'Design & analysis of miniaturized asymmetric coplanar strip fed antenna for multi-band WLAN/WiMAX applications', Prog. Electromagnet. Res. C, 2015, 57, pp. 159– 171 [10]Polli, G., Palomba, M., Colangeli, S., et al.: 'Resistive bias network for optimized isolation in SPDT switches'. Proc. Microwave, Radar and Wireless Communications (MIKON), 2016 21st International Conf., May 2016, pp. 1– 4 [11]Shairi, N.A., Zakaria, Z., Zobilah, A.M.S., et al.: 'Design of SPDT switch with transmission line stub resonator for WiMAX and LTE in 3.5 GHz band', ARPN J. Eng. Appl. Sci., 2016, 11, (5), pp. 3198– 3202 [12]Jost, M., Reese, R., Pauls, J., et al.: 'Comparison of hollow waveguide and dielectric fibre based SPDT switches for w-band'. Proc. Microwave Conf. (GeMiC), Bochum, Germany, March 2016, pp. 140– 143 [13]Shairi, N.A., Ahmad, B.H., Wong, P.W.: 'Switchable radial stub resonator for isolation improvement of SPDT switch'. Proc. Int. J. Eng. Technol., February 2013, pp. 460– 467 [14] 'Microwaves and RF', http://mwrf.com/components/design-spdt-switch-wimax, accessed December 2016 [15]Tsai, G., Chou, P., Chang, C.: 'X-band three-stub filter embedded SPDT switch using packaged PIN diodes and novel resonators'. Proc. 2015 Asia-Pacific Microwave Conf. (APMC), December 2015, pp. 2– 4 [16]Dyskin, A., Peleg, N., Wagner, S., et al.: 'An asymmetrical 60–90 GHz single-pole double-throw switch MMIC'. Proc. 2013 European Microwave Integrated Circuits Conf. (EuMIC), Europe, January 2013, pp. 145– 148 [17]Park, P., Shin, D.H., Yue, C.P.: 'High-linearity CMOS T/R switch design above 20 GHz using asymmetrical topology and AC floating bias', IEEE Trans. Microw. Theory Tech., 2009, 57, (4), pp. 948– 956 [18]Palomba, M., Cleriti, R., Colangeli, S., et al.: 'Design procedure for compact asymmetric SPDT switches and full x-band demonstrator', Int. J. Microw. Opt. Technol., 2014, 9, (1), pp. 78– 82 [19]Takahashi, K., Okamura, S., Wang, X., et al.: 'A capacitance compensated high isolation and low insertion loss series PIN diode SPDT switch'. Proc. Microwave Conf. (EuMC), 2011 41st European, October 2011, pp. 583– 586 [20]Hindle, P.: 'The state of RF and microwave switches', Microw. J., 2010, 53, (11), p. pp. 20 [21]Berezniak, A.F., Korotkov, A.: 'Solid-state microwave switches: circuitry, manufacturing technologies and development trends. Review (part 2)', Radioelectron. Commun. Syst., 2013, 56, (5), pp. 213– 226 [22]Yamane, D., Seita, H., Sun, W., et al.: 'A 12-GHz DPDT RF-MEMS switch with layer-wise waveguide/actuator design technique'. Proc. Micro Electro Mechanical Systems, 2009. MEMS 2009. IEEE 22nd International Conf., January 2009, pp. 888– 891 [23]Lau, T.L., Neoh, S.C., Marzuki, A.: 'An optimization of 15.12 GHz SPDT switch using particle swarm optimization algorithm'. Proc. 4th International Conf. on Intelligent and Advanced Systems (ICIAS2012), June 2012, pp. 175– 178 [24]Lee, W.S., Lee, G.M., Choi, B.C., et al.: 'A band-rejection type RF switch based on a dual-mode microstrip ring resonator', Microw. Opt. Technol. Lett., 2010, 52, (4), pp. 947– 950 [25]Application Note: ' Understanding RF/microwave solid state switches and their applications' ( Agilent Technologies, 2009), pp. 1– 20 [26]Sim, S., Jeon, L., Kim, J.: 'A compact x-band bi-directional phased-array T/R chipset in 0.13 m CMOS technology', IEEE Trans. Microw. Theory Tech., 2013, 61, (1), pp. 562– 569 [27]Nazir, M.U., Kashif, M., Ahsan, N., et al.: 'PIN diode modelling for simulation and development of high power limiter, digitally controlled phase shifter and high isolation SPDT switch'. Proc. Applied Sciences and Technology (IBCAST), 10th International Bhurban Conf., January 2013, pp. 439– 445 [28]Abdul Hadi, M.H., Ahmad, B.H., Wong, P.W., et al.: 'An overview of isolation improvement techniques in RF switch', ARPN J. Eng. Appl. Sci., 2014, 9, (3), pp. 342– 348 [29]Shairi, N.A., Ahmad, B.H., Zakaria, Z., et al.: 'Isolation improvement of SPDT discrete switch with single switchable open stub resonator at 2 GHz band'. Proc. Wireless Technology and Applications (ISWTA), 2012 IEEE Symp., September 2012, pp. 51– 55 [30]Chen, H., Che, W., Zhang, T., et al.: 'SIW SPDT switch based on switchable HMSIW units'. Proc. Electromagnetics: Applications and Student Innovation Competition (iWEM), 2016 IEEE International Workshop, May 2016, pp. 6– 8 [31]Malek, F., Zulkifli, M.S., Affendi, N.A.M., et al.: 'Complementary structure of quadruple p-spiral split ring resonator (QPS-SRR) on modified minkowski patch antenna design'. Proc. Applied Electromagnetics (APACE), IEEE Asia-Pacific Conf., December 2012, pp. 142– 147 [32]Wang, Z., Park, C.: 'Novel wideband GaN HEMT power amplifier using microstrip radial stub to suppress harmonics'. Proc. Microwave Symp. Digest. IEEE MTT-S International, June 2012, pp. 5– 7 [33]Xu, J., Wu, W., Kang, W., et al.: 'Compact UWB bandpass filter with a notched band using radial stub loaded resonator', Microw. Wirel. Components Lett. IEEE, 2012, 22, (7), pp. 351– 353 [34]Nornikman, H., Ahmad, B.H., Abdul Aziz, M.Z.A., et al.: 'Effect of spiral split ring resonator (S-SRR) structure on truncated pyramidal microwave absorber design'. Proc. Antennas and Propagation (ISAP), 2012 International Symp., November 2012, pp. 1188– 1191 Citing Literature Volume11, Issue6May 2017Pages 844-851 FiguresReferencesRelatedInformation
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