Signal generation, control, and frequency conversion AlGaN/GaN HEMT MMICs

We review the design and experimental results of three new AlGaN/GaN high electron-mobility transistor monolithic microwave integrated circuits: a voltage-controlled oscillator (VCO), a single-pole-double-throw switch (SPDT), and a resistive field-effect transistor mixer. The VCO exhibits frequency range between 8.5-9.5 GHz with maximum output power of 35 dBm (at V_ds=30 V) across a 50-Ω load. The L/S band SPDT switch at 0.9, 1.8, and 2.1 GHz was measured to have 0.87-, 0.96-, 1-dB insertion loss and 46-, 42-, and 41-dB isolation, respectively. The switch also shows linear performance for the power levels up to 1 W in the insertion mode. A singly ended X-band resistive mixer has exhibited very low intermodulation, less than -60 dBc for the second and third harmonics of the IF at the RF power level of 10 dBm, and high power handling, P_{1 dB} is estimated to be at least 1 W, with the conversion loss of 17 dB.