Temperature Dependency (25 C - 400 C) of a Planar Folded Slot Antenna on Alumina Substrate

The dependency of planar folded slot antenna characteristics fabricated on alumina substrates over the temperature range of 25 to 400
C are presented. The 3.575 GHz antenna is fed by a 20 mm long, 50 CPW line (S = 130 and W = 60 μm), and there is no ground plane on the back side of the substrate. An on-wafer TRL calibration was used to deembed the CPW feed line for return loss measurements and to measure the increase in the effective dielectric constant and attenuation of the CPW lines as a function of temperature. The measured antenna characteristics show that the resonant frequency varies by less than 1%, the minimum return loss increases from 11 to 16 dB, the quality factor increases from 25.5 to 44.75, and the gain decreases by 1 dBi as temperature is increased from 25C to 400C. Finally, the effect of the measurement test setup on the measured radiation patterns is discussed.