PIN diode switch are usually realised in finline configuration at mm- wave frequencies. But in some applications, waveguide configuration is preferred. This paper deals with the design and development of waveguide PIN diode switch at Ka-band using Alpha Industries, USA make limiter diode CLA3131. The diode was kept at the end of a coaxial line which is coupled to the wave- guide by the extension of the centre conductor of the coaxial line. The circuit is optimised by varying the impedance of the coaxial line, length of the post, diameter of the post and reducing the height of the waveguide to get minimum insertion loss and maximum isolation. Insertion loss of 1.6 dB and isolation of 20.4 dB are achieved at 27 GHz.
B. K. Sarkar, B. K. Sarkar,
"Waveguide pin diode switch at Ka-band", Proc. SPIE 1929, 17th International Conference on Infrared and Millimeter Waves, 192950 (14 December 1992); doi: 10.1117/12.2298297; https://doi.org/10.1117/12.2298297