Design of a 75-140 GHz high-pass printed circuit board dichroic filter

Dong Hwi Kim; Wahab Mohyuddin; Dong Sik Woo; Hyun Chul Choi; Kang Wook Kim

doi:10.1063/1.4977935

Design of a 75-140 GHz high-pass printed circuit board dichroic filter

Rev Sci Instrum. 2017 Mar;88(3):034704. doi: 10.1063/1.4977935.

Authors

Dong Hwi Kim¹, Wahab Mohyuddin¹, Dong Sik Woo², Hyun Chul Choi¹, Kang Wook Kim¹

Affiliations

¹ School of Electronics Engineering, Kyungpook National University, 80, Daehak-ro, Buk-gu, 41566 Daegu, South Korea.
² Department of Aviation Information and Communications Engineering, Kyungwoon University, 730, Gangdong-ro, Sandong-myeon, 39160 Gumi, South Korea.

PMID: 28372442
DOI: 10.1063/1.4977935

Abstract

A new high-performing PCB (Printed Circuit Board) dichroic filter, which can be used for the KSTAR (Korea Superconducting Tokamak Advanced Research) electron cyclotron emission imaging system, is proposed. The current dichroic filter consists of a triangular lattice array of circular holes on the 6-mm thick metal plate, while circular hole spacing limitation caused relatively narrow passband (∼20 GHz). On the other hand, the proposed PCB dichroic filter utilizes the inexpensive commercial PCB fabrication process with a flexible adjustment of circular hole spacing. Therefore, the proposed PCB dichroic filter provides significantly wider passband (∼60 GHz with 0.84 dB insertion loss) with much reduced weight and expense. Also, it is shown that a steep skirt property can be obtained with the thick PCB filter substrate. The design process, fabrication, and measurement results of the new PCB dichroic filter are described.