Characterization of wideband square spiral inductors based on 0.15 µm GaAs pHEMT technology

This paper reports on the characterization of non-scalable square spiral inductors based on 0.15 μm GaAs pHEMT technology. The effect of number of turns on the electrical characteristics of the spiral inductors were characterized up to 40 GHz with inductances values obtained from 0.241 to 2.436 nH. The inductance and self resonant frequency (SRF) of the square spiral inductors were determined by S-parameter simulations from the Smith chart. Results show that the spiral inductors have resonance frequencies ranging from 13.52 GHz to more than 30 GHz for spiral inductors values from 2.436 nH to 0.241 nH. Using tune-tank circuit topology, the Q factor obtained for the spiral inductors have values ranging from 11 to 16. The spiral inductors behavior was finally represented by a π-network equivalent circuit based from on-wafer S-parameter measurement.