David J. Seymour

X-band monolithic GaAs PIN diode variable attenuation limiter

Monolithic GaAs PIN diode attenuator/limiter circuits have demonstrated 26 dB of variable attenuation at X-band, while maintaining under 1.5 to 1 input and output voltage standing wave ratios (VSWRs). Insertion loss is 0.8 dB at 10 GHz in the zero bias condition. Passive limiting provides 15 dB of isolation at RF input power of 2.0 W CW (continuous wave). These results are obtained using a vertical pin diode process on metallorganic chemical vapor deposition (MOCVD) material.<<ETX>>

100 MHz to 20 GHz monolithic single-pole, two-, three-, and four-throw GaAs PIN diode switches

Monolithic GaAs p-i-n diode single-pole, two-, three-, and four-throw switch circuits provide low noise figure and insertion loss performance over a two-decade+one-octave bandwidth. From 100 MHz to 20 GHz, the measured noise figure and insertion loss for the three switch types are less than 1 dB in the through path, with greater than 45 dB of isolation in the off paths. These state-of-the-art results are obtained using a vertical p-i-n diode process on metallorganic chemical vapor deposition (MOCVD) material. Each of the three p-i-n diode switch types has been designed with and without on-chip bias networks. The authors compare the performance demonstrated by this family of six single-pole, two-, three-, and four-throw switch circuits.<<ETX>>

Monolithic MBE GaAs Pin Diode Limiter

A broadband MBE GaAs PIN/NIP diode limiter has demonstrated 15 dB of isolation with a +32.5 dBm input signal while maintaining less than 0.25 dB of small-signal insertion loss from 0.05 GHz to 14 GHz. These results were obtained by incorporating vertical GaAs PIN/NIP diodes in a shunt-loaded microstrip configuration.

X-band and Ka-band monolithic GaAs PIN diode variable attenuation limiters

A description is given of monolithic GaAs p-i-n diode limiter circuits that have demonstrated 20 dB of variable attenuation at X-band and Ka-band while maintaining under 1.5:1 input voltage standing-wave ratio (VSWR). Insertion loss is 0.5-dB at 10 GHz and 1.4-dB at 36.5 GHz in the 0-mA bias condition. Passive limiting provides 7-dB of isolation at radio frequency (RF) powers up to 1.5 W (30% duty cycle). The process used to fabricate the variable attenuation limiter is compatible with FET circuits, allowing integration of other MMIC components on the same substrate for future single-chip radar front ends. Several of these circuits have been fabricated and RF tested. Fabrication, circuit design, and RF performance are discussed.<<ETX>>

A monolithic 2-20 GHz GaAs pin diode SP16T switch

A broadband, monolithic, single-pole, sixteen-throw (SP16T) switch has been fabricated using GaAs vertical PIN diodes. The SP16T switch features less than 4.5-dB insertion loss with greater than 35-dB isolation across the 2-20-GHz band. A novel de-embedding scheme used for switch characterization is also introduced.<<ETX>>

CFET-a new high quality MMIC control device

A new GaAs device developed for use in microwave monolithic control circuitry has been demonstrated. Known as a CFET, for Control Field Effect Transistor, this device eliminates the need for a conventional submicron gate by achieving control by use of a gate located behind the source-drain channel. The resulting capacitance is smaller than a conventional MESEET, resulting in a figure of merit of 800 GHz as compared to 250 GHz for a conventional MESFET. The device capabilities are demonstrated by measured performance of a SPDT switch providing 0.35-dB insertion loss and 20-dB isolation over the DC -10.0-GHz frequency band.<<ETX>>