Measurements of micromachined submillimeter waveguide circuits

• Published in: 2010 76th ARFTG Microwave Measurement Conference pp. 1 - 4
• Main Authors: Xiaobang Shang, Lancaster, M J, Maolong Ke, Yi Wang
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.11.2010
• Subjects: Extraterrestrial measurements; Fasteners; Flanges; Inductors; Insertion loss; Loss measurement; Metals; micromachining; microwave measurement; submillimeter wave devices; WR-3 waveguide
• ISBN: 9781424474479; 1424474477
• DOI: 10.1109/ARFTG76.2010.5700055

In this paper two calibrated measurement methods for submillimeter circuits are presented and micromachined waveguides operating between 220 and 325 GHz have been fabricated using thick SU-8 photoresist technology and tested. The first measurement method is achieved by employing a pair of micromachined embedded H-plane bends, which were specially designed to enable direct and accurate connection between the micromachined circuit and standard waveguide flanges. A 16 mm long WR-3 waveguide has been designed, fabricated and measured using this technology. The measured average insertion loss is 2.3 dB or 0.144 dB/mm over the frequency range of 220-321 GHz. The second measurement technology employs a conventionally machined metal block constructed with two separate pieces in which to mount the micromachined circuit. A choke flange has been adopted for eliminating the effect of air gap at the interfaces between the micromachined circuit and metal block. A 15 mm long WR-3 straight waveguide has been fabricated and tested. The measured insertion loss is between 1.4 dB and 3.2 dB corresponding to 0.093 and 0.213 dB/mm. A comparison between these two measurement technologies has been carried out and presented.