An Improved Multi-Layer Quadrature Coupler for MMICs

Lucyszyn, S.; Robertson, I.D.

doi:10.1109/euma.1991.336501

Cited by 7 publications

(1 citation statement)

References 6 publications

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“…This broadside coupler design was later modified to realise an improved offset-multilayer coupler [9]. When compared to a traditional Lange coupler, its measured results indicated the same badwidth performance while requiring only half the amount of active GaAs area.…”

Section: M()no2l1tiic Realiati()n-mentioning

confidence: 96%

Monolithic Analogue Phase Shifter and Cascode FET Amplifier using Uniplanar Techniques

Lucyszyn¹,

Robertson²,

Aghvami³

1994

24th European Microwave Conference, 1994

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836 4781 ABSTR&AC A precision millimetre-wave analogue phase shifter and a miniature Ku-band cascode FE amplifier are presented. Both MMICs are realised using uniplanar technology. The phase shiftm employs a blend of coplanar waveguide and multilayer techniques. It has a worst-case rms phase error of only ±1.00, for all levels of relative phase shift up to 1200, across the 31 to 32 GHz frequency range. The amplifier is realised using a combination of coplanar waveguide, meandered 'thin-film' microstrip, and lumped elements. The amplifier has an active area of only 0.9 mm2 and a measured gain of over 12 dB at 15 GHz. QbRDUCTIONUntil recently, almost all MMIC designs were based on the microstrip transmission line medium. This is largely because of its convenience, and because so much work has been done to characterise the electrical parameters of microstrip elements. Most computer-aided design packages incorporate a large range of microstrip standard components and discontinuities. However, the major disadvantage of microstrip for MMICs is that the coupling between adjacent microstrip transmission lines and components requires that they be carefully spaced apart, increasing the chip size and leading to higher costs. Also, components can only be grounded effectively at microwave frequencies by employing through-substrate via-holes. A:s a result of the effort to reduce chip sizes and costs, there is now considerable interest in the use of alternative transmission-line media. The main transmission line types of interest are coplanar waveguide (CPW) slotline, and thin-film microstrip (TFMS) --all of which can be used in the same circuit design.`The generic terit 'uniplanar' MMIC [1] is used to describe these types of circuits because the circuitry is confmed to just the front-face of the chip. The back-face ground-plane and through-substrate vias are no longer needed. The first completely uniplanar MMIC-based modules were demonstrated by NTT [2,3]. At millimetric frequenwies, much has been reported on monolithic mixers, using Schottky barrier diodes, and hybrid frequency multipliers, usimg p-n junction varactor diodes. However, little has been reported on millimetre-wave monolithic analogue phase shiftets. One exception to this is the work by Pao, et al.,[4] demonstrating a 60 GHz analogue phase shifter, realised using microstrip technology. Here, interdigitated p-n junction varactor diodes were employed in two single-bit branch-line phase shifters connected in cascade. The results demonstrated a worst-case mis phase error of ±21.00, for a maximum relative phase shift of 1600, across aX59 to 61 GHz fiequency range. Also, within this frequency range, the mean level of insertion loss was 6dB with a worst-case rms amplitude error of ±1.8dB. No results were given for the return loss perfonnances. Precision analogue phase shifters, where the worst-case rms phase error is less than approximately ±1.00, are very difficult to realise at millimetric frequencies, particularly with a monolithic implementation. This is because the...

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Section: M()no2l1tiic Realiati()n-mentioning

confidence: 96%