Wadim Stein

Design and Fabrication of Broadband Hybrid GaAs Schottky Diode Frequency Multipliers

Frequency extender modules of vector network analyzers and signal generators, as well as front-end modules of semiconductor automatic test systems, make use of broadband resistive diode frequency multipliers. This paper presents the design and fabrication of innovative planar varistor frequency multipliers. Three frequency triplers (#1, #2, #3) and two frequency doublers (#4, #5), operating in the 60-110 GHz and 50-110 GHz frequency ranges, respectively, are designed. The hybrid architecture utilizes commercial gallium arsenide Schottky diodes from United Monolithic Semiconductors on thin-film processed high-permittivity alumina substrate. Synthesis is based on a co-simulation procedure between 3-D electromagnetic field and nonlinear harmonic balance circuit simulations. Scalar and spectral measurement data over the focused output frequency ranges are presented. Conversion loss values around 18 dB from 60 to 95 GHz and below 22 dB from 60 to 110 GHz are achieved with frequency tripler #1. Frequency doubler #5 achieves conversion loss values below 15 dB from 50 to 89 GHz and below 22 dB from 50 to 110 GHz. A comprehensive comparison of the presented work with reported frequency multipliers is included.

Planar varistor mode Schottky diode frequency tripler covering 60 GHz to 110 GHz

Frequency extender modules of vector network analyzers (VNA) and signal generators, as well as front end modules of semiconductor automatic testsystems (ATS) make use of broadband resistive diode frequency multipliers. We present the design and construction of a planar varistor tripler utilizing commercial gallium arsenide (GaAs) Schottky diodes on thin-film processed alumina (Al2O3) substrate. Synthesis is based on a co-simulation procedure between 3D electromagnetic field (EM) and nonlinear circuit simulations. Measurement data over the focused output frequency range from 60 GHz to 110 GHz is presented.

Planar cross-polarized transition to a circular waveguide feed for a 61 GHz dielectric antenna

This paper presents a novel concept for a planar cross-polarized transition to a 61 GHz dielectric lens antenna. The transition to the circular waveguide antenna feed consists of a combination of a microstrip line and a slot line. Each of these planar waveguides excites the H11 mode in the circular waveguide with a 90± polarization angle to one another. The developed double layer transition topology was realized on a Rogers 5880 substrate employing the microstrip line on the top and the slot line on the bottom layer. The concept was implemented and tested on a circular waveguide-fed dielectric lens antenna for a 61 GHz radar system. Experimental results show a transition loss of around -2 dB for the microstrip and -3 dB for the slot line feed with excellent crosstalk suppression greater than 40 dB for the two polarization channels. The bandwidth of the built crosspolarized transition is greater than 10 GHz. The results prove that the novel transition concept is very well suited for compact, broadband and low cost polarimetric millimeter-wave radar systems.