SP4T Switch Research Articles

A High-Performance, Low-Cost, and Integrated Hairpin Topology RF Switched Filter Bank for Radar Applications.

Switched filter banks find widespread application in frequency-hopping radar systems and communication networks with multiple operating frequencies, especially in situations demanding elevated filter element isolation. In this paper, the design and implementation of a highly isolated switchable narrow-bandpass filter bank architecture using hairpin microstrip topology is presented. The filter bank has four discrete bandpass filters with passbands of 2.0-2.2 GHz, 2.3-2.5 GHz, 3.1-3.3 GHz, and 3.9-4.1 GHz. These filters span the radar S-frequency band (2.0-4.0 GHz). In order to switch between channels with a switching speed of nanoseconds, low-loss and highly isolated SP4T switches are implemented. Advanced design system (ADS) software is used to design the various filter functionalities, and the entire system is tested on a vector network analyzer (VNA). The proposed architecture makes it much easier to put the filter bank into practice and switch it to the desired frequency, which is useful for radar receiver applications.

Reconfigurable Antenna Booster System for Multiband Operation in IoT Devices With an SP4T Switch

Reconfigurable Antenna Booster System for Multiband Operation in IoT Devices With an SP4T Switch

A Double Fourier-Transform Imaging Algorithm for a 24 GHz FMCW Short-Range Radar.

A frequency-modulated continuous-wave radar for short-range target imaging, assembling a transceiver, a PLL, an SP4T switch, and a serial patch antenna array, was realized. A new algorithm based on a double Fourier transform (2D-FT) was developed and compared with the delay and sum (DAS) and multiple signal classification (MUSIC) algorithms proposed in the literature for target detection. The three reconstruction algorithms were applied to simulated canonical cases evidencing radar resolutions close to the theoretical ones. The proposed 2D-FT algorithm exhibits an angle of view greater than 25° and is five times faster than DAS and 20 times faster than the MUSIC one. The realized radar shows a range resolution of 55 cm and an angular resolution of 14° and is able to correctly identify the positions of single and multiple targets in realistic scenarios, with errors lower than 20 cm.

A 2.4-GHz Fully-Integrated GaAs pHEMT Front-End Receiver for WLAN and Bluetooth Applications

This paper describes a 2.4-GHz fully-integrated front-end receiver including a single-pole triple-throw (SP3T) switch and a low-noise amplifier (LNA) with bypass function, which was fabricated in a 0.25 μm GaAs pHEMT process. An asymmetrical SP3T switch architecture is incorporated to enable the receiver to operate in four modes. The exploration of impedance and voltage gain behavior of the proposed LNA help to establish the matching network and alleviate the trade-off between noise figure (NF) and gain performance. In LNA high gain mode, the implemented front-end receiver shows 1.7 dB of NF and 6dBm of input third-order intercept point (IIP3) with 20 dB of power gain drawing 11 mA of current from 5 V power supply at 2.4 GHz. All input and output return loss had exceeded 10 dB with fully on-chip impedance matching network. In bypass mode, the measured insertion loss of typically 7.5 dB is achieved.

An SISL-Based 24-GHz FMCW Radar With Self-Packaged Six-Port Butler Matrix Receiver

A 24-GHz frequency modulated continuous wave (FMCW) radar system with self-packaged six-port Butler matrix receiver using substrate integrated suspended line (SISL) platform is proposed in this article. Since all active and passive components are integrated on the SISL platform using the standard printed circuit board (PCB) process, the proposed system is highly integrated with low cost. The system is composed of a transmitting (TX) antenna, a Butler matrix with a receiving (RX) antenna array, a single pole four throw (SP4T) switch, a low noise amplifier (LNA), and a six-port receiver. The Butler matrix and SP4T switch are implemented for beam scanning, which has the advantages of low loss and compact size. The SISL-based six-port receiver is designed for quadrature downconversion. The supporting digital signal processing algorithms are also proposed for the calculation and display of multiple targets information. The radar system has shown excellent performance in the measurement of indoor environment, including range, velocity, and direction of arrival (DOA). The proposed radar provides a new solution for a transceiver system.

A Reconfigurable LTE Full-Band Antenna for Smartphones With High Screen-to-Body Ratio

A frequency-reconfigurable antenna with a compact size of 32.5 × 4 mm² suitable for high screen-to-body ratio smartphones is proposed to work in the full LTE band of 698–960 MHz and 1710–2690 MHz. The antenna is physically realized on the metal frame by inserting gaps on the top of metal frame and introducing a shorting stub. The practical environment including the surrounding components and modules is fully considered throughout the antenna design process. The low and high frequency band of this antenna is achieved by activating four and six different SP4T switch states, respectively. The effect of the switch's position on the antenna performance is also investigated. The proposed antenna maintains radiation efficiencies higher than −7 dB at the low frequency band and higher than −5 dB at the high frequency band. The OTA results demonstrate the antenna can be a good candidate in smartphones.

Frequency-Reconfigurable SP4T Switch With Plaid Metal Transistors and Forward Body Biasing for Enhanced RON × COFF Characteristics

A frequency-reconfigurable SP4T switch is presented, in which <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}_{\text {ON}} \times {C}_{\text {OFF}}$ </tex-math></inline-formula> characteristics of switch transistors are enhanced with plaid metal transistors and forward body biasing. Plaid metal transistors (PMT) with forward body bias (FBB) are used for all of the transistors to enhance the FoM. The plaid patterned metal accesses of a transistor for the source and drain decrease the extrinsic resistance and capacitance. FBB increases the overdrive voltage of a transistor and decreases the on-resistance. The SP4T switch includes main switch matrices that route an input signal to four-outputs, a switched inductor (SI) network, and a mode-selection switch. The SI network connected through the mode-selection switch resonates out the off-capacitances of the main switch matrices at RF in the RF mode. The SP4T switch operates without the SI network in DC mode. The SP4T switch is implemented in a 28-nm FDSOI CMOS process. The core area occupies 0.2 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The switch shows less than 2 dB insertion loss from DC to 4.4 GHz in the DC mode and from 4.4 to 5.3 GHz in the RF mode, where isolations are more than 16.8 dB and 18 dB, respectively.

A Reconfigurable Metal Rim Antenna With Smallest Clearance for Smartphone Applications

In this paper, a reconfigurable metal rim antenna with a small clearance and compact structure for 4G/5G smartphones is proposed. It consists of the system ground plane and a metal rim with two slits, in which a U-shaped slot of 1 mm (the smallest) clearance is realized between the system ground and metal rim. The theory of characteristic modes is applied to analyze the eigenmodes of the antenna so as to aid the optimum design. The characteristic modes (CMs) in the band of interest are studied, and an inductive coupling exciter is identified as the best since three CMs can therefore be generated in the lower frequency band (0.69-0.96 GHz), and an SP4T switch can be utilized to increase the bandwidth of the whole lower band. A prototype antenna of the optimized design was fabricated. A good agreement was obtained between the measured and simulated results. The 6-dB frequency bands are the lower band (0.69-0.96 GHz), the middle band (1.7- 2.7 GHz), and the higher 5G band (3.4- 3.6 GHz), respectively, and the total efficiencies are over 50% in all these frequency bands. They indicate that the antenna is a very good candidate for smartphone applications.

Electronically Pattern Reconfigurable Antenna for IoT Applications

In this paper, an electronically pattern reconfigurable antenna for Internet of Things (IoT) applications is presented. The antenna consists of 4 wire-patches sharing the same ground plane. This radiating element can switch between four end-fire radiation states in less than 5 us and achieves a 290 MHz frequency bandwidth from 2.25 to 2.54 GHz. The results show that this antenna can realize a peak gain of 3.9 dBi at 2.44 GHz and a front-to-back ratio greater than 6.5 dB. A single low-power, low-insertion loss SP4T switch enables the radiation pattern steering. This approach avoids the use of multiple electronic components in the reconfiguration mechanism, thus accommodating the IoT microcontroller’s limited resource constraints. The antenna structure is compact and printed on two cost-effective FR-4 printed circuit boards (PCBs). Thanks to its high performance, small size, low cost, and low-power characteristics, the proposed structure is suitable for IoT applications.

A BPF Integrated SP4T Switch Using Parallel Switched Fractal Common Feeding Line

This brief presents a method to design bandpass filter (BPF) integrated single-pole quadruple-throw (SP4T) switch by using parallel switched fractal common feeding line. The common feeding line with fractal design can provide four identical coupling paths for cascading switchable bandpass filters (SW-BPFs), which guarantees the consistency of channel electrical performance. The parallel switches are loaded on the fractal common feeding line, so as to decrease the impact of accumulated residual admittances from OFF-state channels. The SW-BPF is realized by the p-i-n diodes loaded tri-mode resonator (TMR), and the transmission zeros due to the intrinsic property of TMR and the source-load coupling are introduced on both sides of ON-state bandpass passband to improve the selectivity. The high suppression property of detuned TMR forms the OFF-state channel. As an example, a single-layer BPF integrated SP4T switch with the central frequency (CF) of 1.0 GHz and the ripple bandwidth (RBW) of 80 MHz is designed and fabricated to validate the proposed design concept.

Loss Compensated PCM GeTe-Based Latching Wideband 3-bit Switched True-Time-Delay Phase Shifters for mmWave Phased Arrays

This article reports the first implementation of 3-bit millimeter-wave switched true-time-delay (TTD) phase shifters based on phase-change material (PCM) germanium telluride (GeTe). Two TTD phase shifters are presented. The first phase shifter is designed using four monolithically integrated PCM single-pole triple-throw (SP3T) switches to route the signal through delay lines. The insertion loss variation between various states is minimized by integrating two fixed PCM GeTe elements maintained in the crystalline state, along with the optimized width of the delay lines. The PCM switching cells are latching type, thus, consume no static dc power. The SP3T switches are connected back-to-back in two stages to provide a 3-bit phase shift with 20° precision. The second phase shifter is designed using two back-to-back connected PCM single-pole eight-throw (SP8T) switches. Both phase shifters are designed to operate over an 8 GHz wide frequency band with a center frequency of 30 GHz. The devices are fabricated in-house using an eight-layer microfabrication process. The proposed devices are highly miniaturized with an overall device area of 0.42mm 2 and 1.4mm 2 for the first and second phase shifter, respectively. The first phase shifter exhibit a measured average loss of 4.3 dB with a variation of ±0.3 dB and a return loss better than 20 dB, while the second phase shifter demonstrates low average measured loss of 3.8 dB with only ±0.2 dB loss variation and returns loss better than 17 dB at 30 GHz. Both phase shifters provide 180° linear phase shift with lower than 18 ps delay in the worst case.

Digitally-Controlled Bondwire Inductor with High Quality Factor and Wide Tuning Range

A tunable bondwire inductor (TBI) with high-quality factor and wide tuning range is presented. The proposed TBI is fabricated on a single chip by combining a single-pole four-throw (SP4T) switch integrated circuit (IC) and four bondwire inductors on a package substrate. The SP4T switch IC is fabricated using 180 nm silicon-on-insulator (SOI) complementary metal-oxide-semiconductor (CMOS) technology. The fabricated TBI chip exhibits a 521% tuning range of inductance from 1.77 to 11 nH at 0.1 GHz and a relatively high-quality factor. To the knowledge of the authors, the results of this work demonstrate the best combined performance of inductance tuning range and quality factor.

A New mm-Wave Multiple-Band Single-Pole Multiple-Throw Switch With Variable Transmission Lines

This article a new multiple-band single-pole N-throw (SPNT) switch topology suitable for mm-wave applications. Compared to a conventional shunt-type SPNT switch, the proposed SPNT operates in the multiple frequency bands by adopting a variable transmission-line (T-line) structure. The variable T-line (VTL) structure consists of multiple sections of T-line and multiple shunt switches. Therefore, it realizes a variable quarter-wave line at different frequencies depending on the ON–OFF configuration of the multiple shunt switches. To validate the proposed topology, two versions of a triple-band SP3T switch operating at 20, 30, and 40 GHz are demonstrated in a 65-nm bulk CMOS technology. The first version (SW1) employs a minimum number of shunt switches in the VTL structure, thus minimizing the insertion loss. The second version (SW2) includes extra shunt switches in the VTL, thus improving the isolation. The measurement shows that SW1 exhibits insertion loss of 3, 3.4, and 3.6 dB at 20, 30, and 40 GHz, respectively. The isolations are 22.8 or 20 dB at 20 GHz, 18.5 or 21.5 dB at 30 GHz, and 19.7 or 23.5 dB at 40 GHz, depending on the operation mode. On the other hand, SW2 shows improved isolation of 36.2 or 45 dB at 20 GHz, 19.6 or 42.8 dB at 30 GHz, and 22.7 or 38.6 dB at 40 GHz. The insertion losses are 3.6, 3.8, and 3.9 dB at 20, 30, and 40 GHz, respectively.

Parasitic Compensation and Hence Isolation Improvement of PIN Diode-Based Switches

This brief presents a transmission line based resonant technique to nullify the parasitic effect of a PIN diode used to design a narrowband high frequency switch. Resonant condition is obtained by using a section of transmission line in series with a single PIN diode in a shunt branch. The method guarantees isolation improvement at any design frequency lower than the series resonant frequency of a diode. It does not use any lumped component other than those required for biasing. Thus, the method greatly improves the high frequency performance of a PIN diode as a switch. A transmission line based analysis is carried out to obtain the design equations. The theoretical prediction is verified by fabrication and measurement. A single-pole-single-throw (SPST) switch using just one single PIN diode provides measured isolation of 40 dB and insertion loss of 1.5 dB at 10.55 GHz. The return loss is more than 20 dB over 10.2-10.8 GHz. A low cost NXP semiconductors BAP64-02 PIN diode with high parasitic and the manufacturer specified highest frequency as 6 GHz is used to show the competency of the proposed method. A second SPST switch using two diodes provides isolation of 72 dB, insertion loss of 1.8 dB and return loss of 35 dB at 10.55 GHz. An SP4T switch is also fabricated and tested. Measured 1 dB compression point for all the switches is higher than 23 dBm.

Complementary Split-Ring Resonator (CSRR)-Loaded Sensor Array to Detect Multiple Cracks: Shapes, Sizes, and Positions on Metallic Surface

Single-resonance-based radio frequency (RF) resonators cannot detect multiple cracks simultaneously nor localize the position of a crack. To address these drawbacks, we propose a complementary split-ring resonator (CSRR)-loaded array. In this array, there are four channels and each channel consists of three CSRRs, forming a 4 × 3 sensing array that is developed in the ground plane of a microstrip line using a low-cost FR4 substrate. A voltage-controlled oscillator (VCO) generates three discrete frequencies: 1.88 GHz, 2.60 GHz, and 3.61 GHz to each channel, which is sequentially selected using a single-pole four-throw (SP4T) switch. The transmitted RF signals are converted into the DC voltage levels and are interpreted by a microcontroller. Aluminum sheets with cracks embedded in the surface are used to demonstrate the detection of cracks of various shapes, sizes and locations/orientations (horizontal, diagonal, and vertical) with simulations and measurements. The detection of the minimum detectable crack (W c × L c × D c = 1 mm × 10 mm × 0.1 mm) is experimentally verified. Full-length longer cracks (L c = 100 mm) are also detected using our proposed detection system with the SP4T switch in addition to our proposed algorithm that scans the CSRRs of each selected channel.

Reconfigurable dual notch band antenna on Si-substrate integrated with RF MEMS SP4T switch for GPS, 3G, 4G, bluetooth, UWB and close range radar applications

In this paper, a reconfigurable co-planner waveguide (CPW) fed circular shaped monopole ultra wide band (UWB) antenna with dual band notch characteristics based on silicon substrate is presented. The dual notch band characteristics are realized by inserting two slots, namely, U- and I-shaped, in the circular radiating patch to switch-off the WiMAX IEEE 802.16 (3.30–3.80 GHz) and WLAN IEEE 802.11a/h/j/n (5.15–5.35 GHz, 5.25–5.35 GHz, 5.47–5.725 GHz, 5.725–5.825 GHz) respectively. The reconfigurability from antenna is achieved by integrating the radio frequency micro-electro mechanical system based single pole four through (RF MEMS SP4T) switch in the U- and I-shaped slots of radiating patch. The measured results demonstrate the bandwidth of 0.68–16.23 GHz resulting in fractional bandwidth of 183.91%, and are well in accordance with the simulation results. The gain of proposed antenna varies from 2.58 to 5.05 dBi with radiation efficiency of 83–95% and exhibits the omnidirectional like pattern in H-plane and nearly dipole like pattern in the E-plane. Further, the performance of proposed antenna is analyzed by implementing an equivalent RLC resonant circuit model in both the frequency and time domain.

A Quadruple-Polarization Reconfigurable Feeding Network for UAV RF Sensing Antenna

A quadruple-polarization reconfigurable feeding network for an unmanned aerial vehicle (UAV) RF sensing antenna operating at 915 MHz is presented. It consists of one single-pole four-throw (SP4T) switch, one 90° hybrid coupler, two 180° hybrid couplers, and two single-pole double-throw (SPDT) switches. By controlling the SP4T and SPDT switches, quadruple polarizations with two linear polarizations (vertical and horizontal) and two circular polarizations (right-hand and left-hand) were obtained. The proposed reconfigurable feeding network with quadruple polarization modes in the 902–928-MHz range has an insertion loss of approximately 2.5 dB including switch loss, and it achieves amplitude and phase variations of up to approximately 0.5 dB without divided power or switch loss, and 3°, respectively. Using the proposed feeding network, a circular low-profile UAV RF sensing antenna with quadruple polarizations was designed. Its electrical size, 10-dB impedance bandwidths, and a peak gain are approximately $0.57\lambda _{0} \times 0.57\lambda _{0} \times 0.08\lambda _{0}$ at 915 MHz, 16%, and 6 dBi(c), respectively.

Reliable and Compact 3- and 4-Bit Phase Shifters Using MEMS SP4T and SP8T Switches

This paper presents radio frequency (RF) micro-electromechanical system-based 3- and 4-bit phase shifters using single-pole-four-throw (SP4T) and single-pole-eight-throw (SP8T) switches. The design is fabricated on $635~\mu \text{m}$ alumina substrate using a surface micromachining process. SP4T and SP8T switches demonstrate measured return loss of >16 dB, worst case insertion loss of 1.66 dB, and isolation of >13.6 dB up to 40 GHz. Total area of the SP4T and SP8T switches is 0.98 mm2 and 1.66 mm2, respectively. Switches are capable of handling 1 W of incident RF power and can sustain up to 1 billion cycles at 85°C. Finally, 3- and 4-bit phase shifters deliver measured return loss of >12 dB, average insertion loss of 1 billion cycles with 0.1 W of power in cold switching. In addition, phase shifters also worked satisfactory up to >400 million cycles with 0.5 W of power at 85 °C in hot switching condition. Devices were enclosed within a low-cost package and characterized them systematically. [2017-0104]

A Novel Unit Cell for Active Switches in the Millimeter-Wave Frequency Range

This paper presents a novel transistor unit cell which is intended to realize compact active switches in the high millimeter-wave frequency range. The unit cell consists of the combination of shunt and common gate transistor within a four-finger transistor cell, achieving gain in the amplifying state as well as good isolation in the isolating state. Gate width-dependent characteristics of the unit cell as well as the design of actual switch implementations are discussed in detail. To verify the concept, two switches, a single pole double throw (SPDT) switch and single pole quadruple throw (SP4T) switch, intended for the WR3 frequency range (220–325 GHz) were manufactured and characterized. The measured gain at 250 GHz is 4.6 and 2.2 dB for the SPDT and SP4T switch, respectively. An isolation of more than 24 dB for the SPDT switch and 12.8 dB for the SP4T switch was achieved.

Ultra-Wideband Low-Loss Switch Design in High-Resistivity Trap-Rich SOI With Enhanced Channel Mobility

In this paper, the stress memorization technique (SMT) effects upon ultra-wideband RF switch performance are investigated for the first time. Low insertion loss (IL), high isolation, ultra-wideband (dc to 50 GHz) single-pole double-throw (SPDT), and single-pole four-throw (SP4T) switches designed with commercial 0.13- $\mu \text{m}$ high-resistivity (HR) trap-rich SOI technology with/without SMT are presented and investigated. 2.5 V nMOS transistor ( $L_{g} = 0.2~\mu \text{m}$ ) with low $R_{\mathrm{\scriptscriptstyle ON}} {^\ast} C_{\mathrm{\scriptscriptstyle OFF}}$ from GF 130RFSOI PDK is used. It is found that channel mobility of switch transistor is improved by SMT and thus switch performance can be further improved. Moreover, the impact of transistor channel length, which has dominant effects on both IL and isolation of the switches, under different gate bias on switch performance are also studied and verified experimentally. Low measured IL of less than 2.1 dB and good isolation of better than 27 dB from dc to 50 GHz are obtained for the SPDT switch. For SP4T switch, the measured IL of less than 2.6 dB and isolation of better than 27 dB are achieved from dc to 35 GHz. The active chip areas of designed SPDT and SP4T switches are compact with size of only $0.214 \times 0.19~\text {mm}^{2}$ and $0.36 \times 0.19~ \text {mm}^{2}$ , respectively.