Characterisation of terahertz integrated membrane circuits

Licentiate thesis, 2015

In this thesis a novel measurement setup and thru-reflect-line (TRL) calibration kit for vector network analyser (VNA) measurements at 220 GHz to 325 GHz (WR-03) is presented. Measurements on passive membrane circuit devices under test (DUTs) show improvement in the S-parameters compared to a waveguide integrated membrane circuit setup in previous work, especially in reducing the ripples and increasing repeatability of the measurements. VNA measurements provide a challenge when measuring on waveguide integrated membrane circuit devices at terahertz frequencies. In this setup, phase uncertainty in the measurements, due to waveguide width tolerance, is reduced by shortening the access waveguides. Because both waveguide inputs are placed in the same flange, the access waveguides can be made much shorter. However, in order to accommodate different DUT and TRL line lengths, two bends were introduced in each waveguide, and the trade-off between sharper bends or longer access waveguides effect on uncertainty, investigated. By the use of an adapter block, which puts the VNA extender outputs in the same flange, phase uncertainty due to cable flex is eliminated by locking the VNA frequency extenders in position during the entire measurement.