This work describes the design and characterization
of three different 90º phase switches working in the Ka-band.
The phase switch is intended to be part of a radio astronomy
receiver which works in the 26-36 GHz frequency band. The
designs are based on the use of wideband band-pass filters with
single-pole double-throw (SPDT) switches in order to select the
transmission path. The design of the filters are performed in a
5-mils thick Teflon-based substrate (CLTE-XT) microstrip
technology, showing an average phase shift of 89º±4º over the
24-37 GHz band with an amplitude imbalance of 0.1dB. The
switch function is analyzed using three different SPDTs: a PIN
diode based switch, MMIC PIN diode switch and MMIC
pHEMT switch
