Single-pole Single-throw Research Articles

Power-efficient switching-based CMOS UWB transmitters for UWB communications and Radar systems

This paper presents a new carrier-based ultra-wideband (UWB) transmitter architecture. The new UWB transmitter implements a double-stage switching to enhance RF-power efficiency, reduce dc-power consumption, and increase switching speed and isolation, while reducing circuit complexity. In addition, this paper also demonstrates a new carrier-based UWB transmitting module implemented using a 0.18-mum CMOS integrated pulse generator-switch chip. The design of a UWB sub-nanosecond-switching 0.18-mum CMOS single-pole single-throw (SPST) switch, operating from 0.45 MHz to 15 GHz, is discussed. The design of a 0.18-mum CMOS tunable impulse generator is also presented. The edge-compression phenomenon of the impulse signal controlling the SPST switch, which makes the generated UWB signal narrower than the impulse, is described. Measurement results show that the generated UWB signal can vary from 2 V peak-to-peak with 3-dB 4-ns pulsewidth to 1 V with 0.5 ns, covering 10-dB signal bandwidths from 0.5 to 4 GHz, respectively. The generated UWB signal can be tuned to cover the entire UWB frequency range of 3.1-10.6 GHz. The sidelobe suppression in the measured spectrums is more than 15 dB. The entire CMOS module works under a 1.8-V supply voltage and consumes less than 1 mA of dc current. The proposed carrier-based UWB transmitter and the demonstrated module provide an attractive means for UWB signal generation for both UWB communications and radar applications

FET-integrated CPW and the application in filter synthesis design method on traveling-wave switch above 100 GHz

A new transmission-line concept, called the field-effect transistor (FET)-integrated coplanar waveguide (CPW), is proposed. This concept treats the passive two-finger FET as CPW and, thus, the scaling rule is more accurate than the previous model, especially in high frequency. The extraction approach of the parameters of the FET-integrated CPW is also included. With this concept, the design procedure of traveling-wave switches can be equivalent to a filter synthesis problem. Based on this design procedure, a single-pole single-throw and a single-pole double-throw traveling-wave switch have been realized and measured using 0.15-/spl mu/m high-linearity AlGaAs/InGaAs/GaAs pseudomorphic high electron-mobility transistors. Finally, the frequency limitation of the traveling-wave switches is also discussed. The results show the FET-integrated CPW is the most efficient way to overcome the frequency limitations of traveling-wave switches, achieving operation frequency to 135 GHz, the highest frequency reported to date.

Integration of Packaged RF MEMS Switches With Radiation Pattern Reconfigurable Square Spiral Microstrip Antennas

This work describes the integration of commercially available packaged radio frequency microelectromechanical system (RF MEMS) switches with radiation pattern reconfigurable microstrip antennas. Most applications of RF MEMS switches consider the switches as only circuit elements. In contrast, the implementation of packaged switches in this particular antenna must address not only the simple open/closed behavior of the switches but also their impact on the radiation characteristics of the reconfigurable antenna. Here, two Radant MEMS single-pole single throw (SPST) SPST-RMSW100 (packaged RF MEMS) switches are used to reconfigure the radiation patterns of a resonant square spiral microstrip antenna between endfire and broadside over a common impedance bandwidth. Switch insertion, matching network design, and other issues are addressed. Results for both simulated and measured antennas, as well as recommendations for future work in this area, are provided.

A Circularly Polarized Microstrip-Fed T-Slot Antenna Array on a Conducting Cylinder

A circularly polarized T-slot antenna array wrapped on a conductive cylinder is presented in this letter. This cylindrical antenna array consists of four independent cavity-backed T-slot elements, which are fed by four microstrip lines. The designed array is to be used in a switched-beam mode so that the array's radiation beam can be selected using a single-pole 4-throw (SP4T) switching circuit. Simulated and measured results show that the radiation pattern of each element is able to cover a quadrant in the horizontal plane while the radiated wave in each quadrant is circularly polarized. Furthermore, the four elements are well isolated and exhibit wide bandwidth. Measured results of one slot element in the array configuration show that it has a 13.8% bandwidth for $10~ dB$ return loss and a 7% bandwidth for 3 dB axial ratio.

Multiport MEMS-based waveguide and coaxial switches

In this paper, a new concept of three-dimensional (3-D) multiport RF microelectromechanical systems (MEMS) switches is introduced. The proposed structures are based on integrated MEMS actuators inside 3-D waveguide and coaxial structures. These switches are well suited for high-power redundancy switch matrices for satellite communication, as well as millimeter-wave applications. To demonstrate the concept, a C-type waveguide switch is fabricated and tested. The use of a unique bi-layer curled electrostatic actuators, results in a very good RF performance with an isolation of 36-40 dB and a return loss of -20dB over a 7% bandwidth at satellite Ku-band. This paper also presents for the first time a new type of MEMS-based coaxial switch, which can offer a much larger bandwidth with miniaturized dimensions. To prove the concept, prototype units of single-pole single-throw and C-type switches are designed, fabricated, and tested. The measured results demonstrate a bandwidth of 65% for the C-type MEMS-based coaxial switch.

A low-loss single-pole six-throw switch based on compact RF MEMS switches

A low-loss single-pole six-throw (SP6T) switch using very compact metal-contact RF microelectromechanical system (MEMS) series switches is presented. The metal-contact MEMS switch has an extremely compact active area of 0.4 mm /spl times/ 0.3 mm, thus permitting the formation of an SP6T MEMS switch into the RF switch with a total area of 1 mm/sup 2/. The MEMS switch shows an effective spring constant of 746 N/m and an actuation time of 8.0 /spl mu/s. It has an isolation loss from -64.4 to -30.6dB and an insertion loss of 0.08-0.19 dB at 0.5-20 GHz. Furthermore, in order to evaluate RF performances of the SP6T MEMS switch, as well as those of the single-pole single-throw RF MEMS series switch, we have performed small-signal modeling based on a parameter-extraction method. Accurate agreement between the measured and modeled RF performances demonstrates the validity of the small-signal model. The SP6T switch performed well with an isolation loss from -62.4 to -39.1dB and an insertion loss of 0.19-0.70 dB from dc to 6 GHz between the input port and each output port.

A single-pole double-throw (SPDT) circuit using lateral metal-contact micromachined switches

A dc 6 GHz single-pole double-throw (SPDT) switching circuit that employs lateral metal-contact micromachined switches is investigated. The lateral metal-contact switch consists of a set of quasi-finite ground coplanar waveguide (FGCPW) transmission lines and a high-aspect-ratio cantilever beam. A single-pole single-throw (SPST) lateral micromachined switch has an insertion loss of 0.08 dB and a return loss of 32 dB at 5 GHz. The isolation is 32 dB at 5 GHz. The measured insertion loss of the SPDT switching circuit is below 0.75 dB, whereas the return loss is higher than 19 dB at 5 GHz. The isolation at 5 GHz is 33 dB. Pull-in voltage of the switch is 23.3 V and switching time is 35 μs. The size of the SPDT switching circuit is 1.2 mm × 1.5 mm. A main advantage of this circuit structure is simple fabrication process with high yield (>90%) based on the deep reactive ion etching (DRIE) technique of silicon-on-insulator (SOI) wafer and shadow mask technology.

Millimeter-wave MMIC passive HEMT switches using traveling-wave concept

This paper describes the design of millimeter-wave wide-band monolithic GaAs passive high electron-mobility transistor (HEMT) switches using the traveling-wave concept. This type of switch combined the off-state shunt transistors and series microstrip lines to form an artificial transmission line with 50-/spl Omega/ characteristic impedance. A 15-80-GHz single-pole double-throw (SPDT) switch in conjunction with quarter-wavelength impedance transformers demonstrates an insertion loss of less than 3.6 dB and an isolation of better than 25 dB. Another type of wide-band switch was designed by using a series HEMT switch to replace the quarter-wavelength transformer, and the operating band can be extended to dc. With this scheme, dc-80-GHz single-pole single-throw (SPST) and dc-60-GHz SPDT switches are also developed with compact chip size. From dc to 80 GHz, the insertion loss and isolation of the SPST switch are better than 3 and 24 dB, respectively. The SPDT switch has an insertion loss of better than 3 dB and an isolation of better than 25 dB from dc to 60 GHz. The analysis of circuit characteristics and design procedures are also included. It is concluded that the device periphery can be selected for the desired bandwidth, while the number of transistors is decided to achieve the isolation.

EM design of broadband RF multiport toggle switches

Radio frequency (RF) MEMS is an emerging sub-area of MEMS technology that is revolutionizing RF and microwave applications. RF MEMS devices have a broad range of optional applications in military and commercial wireless communication, and navigation and sensor systems. This article presents the EM design of different multiport toggle switches. Such a multiport switch can be used in the compact designs of switching matrices, routing networks, or phase shifters. One application range is the creation of electronically steerable antenna arrays, which can be used for radar applications and satellite communication. The miniaturized switches are based on the single pole single throw (SPST) toggle switch and, in addition to their small size, they have an increased RF performance regarding losses and operation bandwidth (DC to 50 GHz). A 3D FDTD field solver has been used for the electromagnetic design of all the switches. © 2004 Wiley Periodicals, Inc. Int J RF and Microwave CAE 14: 329–337, 2004.

Estimation of equivalent circuit parameters for a millimetre-wave GaAs PIN diode switch

The paper describes a method for estimation of equivalent circuit parameters for a millimetre-wave GaAs PIN diode switch. A GaAs PIN diode with low insertion loss over the millimetre-wave region is presented. The diode has been developed by estimating the parasitic resistance of the space between the P+-layer and the N+-electrode. The design and performance of a broadband single-pole single-throw (SPST) monolithic microwave integrated circuit (MMIC) switch using the GaAs PIN diode developed are also described. An insertion loss of 1.0 dB and isolation of 20 dB were obtained in the range DC to 50 GHz.

Monolithic transistor SPST switch for L-band

A comparison of single-pole single-throw switch topologies is presented in this paper. A three-MESFET monolithic GaAs switch was designed, for 2-GHz operation, fabricated and tested in three different bias conditions: V/sub bias/ = 0 (self-bias); I/sub bias/ = 0 (floating); and V/sub bias/ /spl ne/ 0, I/sub bias/ /spl ne/ 0 (biased). It will be shown that a floating configuration presents on-state lower insertion loss (IL) (/spl sim/1.7 dB). However, the off-state isolation has the same order of magnitude in all three bias conditions (typically 50 dB). Comparing measurements and simulations, the best available nonlinear model for the floating bias operation was selected. Finally, several resonant topologies were studied and a new topology is proposed to increase the off-state isolation without degrading the on-state IL. The advantages and drawbacks of resonant topologies over nonresonant configurations are also discussed, taking into account technology constraints and operation frequency. A solution to reduce the inductor value is proposed.

Metamorphic pin diodes for high isolating and low power consuming millimetre-wave switching MMICs

Two broadband millimetre-wave switching circuits using In0.52Ga0.48As pin diodes grown on a GaAs substrate are presented. To the best of the authors' knowledge, this is the first time that metamorphic pin diodes have been used for switching MMICs. The performances of the pin diodes are discussed and excellent RF results from a single pole single throw (SPST) and single pole double throw (SPDT) switch are demonstrated.

Low-Power Consumption InGaAs PIN Diode Switches for V-band Applications

In this paper, we present the measurement results of two InP-based coplanar SPST (single pole single throw) PIN diode switches operating at V-band frequencies. The switches show excellent mm-wave performance combined with a very low DC-power consumption. The SPST with on-chip biasing and DC-blocking capacitors demonstrates an insertion loss as low as 0.84 dB and a high isolation value of 21.8 dB at a center frequency of 53 GHz with only 0.8 mW of DC-power consumption. A more simple SPST exhibits under equivalent conditions (0.9 mW) an excellent insertion loss of 0.52 dB and an isolation of 21.7 dB. Furthermore the power-handling capability of the InGaAs PIN diodes, which are used as active switching elements, is investigated in this paper and found to exceed 25 dBm at a reverse voltage of -5 V.

Compact DC-60-GHz HJFET MMIC switches using ohmic electrode-sharing technology

Compact DC-60-GHz heterojunction field-effect transistor (HJFET) monolithic-microwave integrated-circuit (MMIC) switches have been demonstrated for millimeter-wave communications and radar systems. To reduce the MMIC chip size, a novel ohmic electrode-sharing technology (OEST) has been developed for MMIC switches with series-shunt FET configuration. Four FET's of the series-shunt single-pole double-throw (SPDT) MMIC switch were integrated into an area of approximately 0.018 mm/sup 2/. The developed MMIC switches have a high power-handling capability with low insertion loss (IL) and high isolation (Iso) at millimeter-wave frequencies. From DC to 60 GHz, the single-pole single-throw (SPST) MMIC switch achieved the IL and Iso of better than 1.64 and 20.6 dB, respectively. At 40 GHz, the IL increases by 1 dB at the input power of 21 dBm. A novel large-signal FET model for the switch circuit is presented. The simulated power-transfer performance shows the excellent agreement with the measured one. The developed MMIC switches will contribute to the low-cost and high-performance millimeter-wave communications and radar systems.

W-band SPST transistor switches

A single-pole, single-throw (SPST) transistor switch has been developed, Three types of switches, that is, GaAs MESFET, AlGaAs-GaAs HEMT, and pseudomorphic HEMT (PM-HEMT), have been fabricated, and the performances at W-band are compared. To reduce on-state resistance and off-state capacitance, gate length was varied as a parameter. Moreover, an inductance for resonance was installed in parallel to the off-state capacitance between source and drain to obtain a high isolation, A relatively low insertion loss of 1.6 dB and a high isolation over 20 dB at W-band have been obtained from the 0.8-/spl mu/m gate length PM-HEMT.

X-band, 0.25 dB loss, high isolation MESFET switch with good input and output match

The design and measured performance of a very low-loss, single pole single throw (SPST) switch operating in the C-X-band frequency range is presented. This MESFET based MMIC switch achieves 0.25 dB insertion loss, high isolation (> 25 dB) and 20 dB input and output return loss in both switch states over the 7 – 9 GHz frequency band. This design is unique in the sense that the switch maintains a very good impedance match in both the operating states without increasing the through insertion loss.

Monolithic FET structures for high-power control component applications

A monolithic FET switch is described that can be integrated with other monolithic functions or used as a discrete component in a microwave integrated circuit structure. This device increases the power-handling capability of the conventional single FET switch by an order of magnitude. It does this by overcoming the breakdown voltage limitation of the FET device. The design, fabrication and performance of two high-power control components using these circuits are described as examples of the implementation of this technology. They are an L-band terminated single-pole, single-throw (SPST) switch and an L-band limiter.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Fin-line PIN-diode attenuators and switches for 94 GHz range

The letter reports new results of fin-line PIN-diode attenuators and switches for the 94 GHz range. Design and performance of SPST and SPDT switches?single-pole single-throw and single-pole double-throw, respectively?will be presented. The attenuation of the SPST switch, for example, can be adjusted between 2 and 35 dB over the entire waveguide band from 75 to 110 GHz.

Dual-gate GaAs FET switches

A set of multi-pole, multi-throw switch devices consisting of dual-gate GaAs FET's is described. Included are single-pole, single-throw (SPST), double-pole, double-throw (DPDT), and single-pole four-throw (SP4T) switches. Device fabrication and measurement techniques are discussed. The device models for these switches were derived based on an equivalent circuit of a duff-gate FET. The devices were found to have substantial gain in X-band and low Ku-band.