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Abstract-Investigations are conducted into low-loss, low-dispersion fully shielded membrane-supported striplines designed for use in a millimeter-wave multi-chip-module. Two types of transmission line are studied: a membrane-supported shielded stripline and a novel variation of this where the membrane material is removed in areas of little mechanical importance to reduce attenuation and dispersion. The latter is possible through the exploitation of a versatile micromachining technique using SU-8 for both the membrane and the shielding. The micromachining techniques used for the fabrication of the microshielding allows for the conformal packaging of lines and devices, with the ultimate aim of the realization of novel components for 3D system-in-a-package type modules. Extensive simulated results obtained from rigorous electromagnetic modeling are presented that fully characterize both types of line and, where possible, are compared to measured results. Loss mechanisms are investigated for both line types and simulations suggest that losses as low as 0.39 dB/cm and effective relative permittivities of less than 1.05 are possible at a frequency of 100 GHz, comparing well with other demonstrated membrane supported transmission lines. The methods used for investigation of line characteristics and analysis of single-mode, nonleaky frequency range are applicable to any variety of membrane supported transmission line. The basics of line fabrication are given along with measurement results and de-embedding techniques used at V-band.

This paper describes a novel method for fast, accurate evaluation of doping-spike carrier concentrations in hot-electron injected GaAs Gunn diodes. The technique relies on current asymmetry measurements obtained using pulsed-dc testing of on-wafer quasi-planar Gunn diode test structures, which removes the need for full device fabrication. Small changes in carrier concentration can easily be detected (at a nominal value of 1 × 10 18 cm −3 ) and a greater sensitivity than conventional techniques is demonstrated at the doping levels used. In addition, test structure fabrication can be integrated into the initial Gunn diode front side production process allowing a rapid in-process test to be carried out thus leading to a significant reduction in material characterization cycle time.

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