A comparative study of active and passive GaAs microwave couplers

This paper compares the design and performance of two types of wide band multi-octave MMIC couplers. An active coupler is based on pHEMT devices and fabricated in a GaAs foundry and a passive coupler uses coplanar waveguide (CPW) multilayer techniques. The multilayer couplers are fabricated on GaAs...

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Bibliographic Details
Published inEuropean Gallium Arsenide and Other Semiconductor Application Symposium, GAAS 2005 pp. 353 - 356
Main Authors Krishnamurthy, L., Sun, Q., Vo, V.T., Parkinson, G., Paul, D.K., Williams, K., Rezazadeh, A.A.
Format Conference Proceeding
LanguageEnglish
Published IEEE 2005
Subjects
Coplanar waveguides
Directional couplers
Distributed amplifiers
Foundries
Gallium arsenide
Microwave devices
MMICs
Nonhomogeneous media
PHEMTs
Wideband
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Summary:This paper compares the design and performance of two types of wide band multi-octave MMIC couplers. An active coupler is based on pHEMT devices and fabricated in a GaAs foundry and a passive coupler uses coplanar waveguide (CPW) multilayer techniques. The multilayer couplers are fabricated on GaAs semi-insulating substrate and are reciprocal and directional. The active coupler design is adapted from the distributed amplifier circuit and is non-reciprocal. On-wafer RF measurements were carried out on the fabricated multilayer directional couplers and pHEMT based couplers. A multilayer quadrature directional coupler with coupling factor of 5 dB and isolation of 10 dB is realized over 10 to 35 GHz. A 180 /spl deg/ coupler using pHEMT devices realized a coupling factor of 5 dB and isolation of 26.5 dB over 2 to 20 GHz. For the first time the relative merits of the performance and implementation of these couplers are compared in view of their respective applications.
ISBN:9788890201202
8890201207