Wide-band PIN diode SPST switch in unilateral asymmetric finline

This paper reports the design and modelling of a wide-band, low insertion l oss finline SPST switch using beam lead PIN diodes at the Ka-band. A unilat eral asymmetric finline with an offset slot has been used to realize a tran smission line with lower impedance to best match the impedance of the diode . Finline tapered transitions have been designed with exponential profiles for minimum reflection coefficient over the band. Wide-band operation, cove ring the full Ka-band, has been achieved with reactive tuning by varying th e diode spacing. Four PIN diodes have been shunt mounted across the unilate ral asymmetric finline slot. An insertion loss of 0.9 dB minimum and 1.65 d B maximum over the entire Ka-band and isolation of >25 dB from 26.5 to 35 G Hz and >20 dB over the complete Ka-band has been achieved.