A K-Band MMIC Cross-Coupled Oscillator With High Output Power in 0.25-μm GaN HEMT

In this letter, a monolithic microwave integrated circuit (MMIC) cross-coupled oscillator with high operating frequency and high output power is proposed using 0.25- $\mu \text{m}$ gallium nitride (GaN) high electron mobility transistor (HEMT) technology. The coupling capacitors in the core circuit are analyzed to obtain high output power with a suitable tank inductor. The $\pi $ -type matching network is adopted to effectively extract the fundamental output signal. Also, a flip-transistor layout with a shared back via is proposed for reduced interconnect loss and a compact layout. With a chip area of only 0.71 mm ² , the measured results demonstrate a maximum output power of 16 dBm at 24.3 GHz, and a phase noise (PN) of −137.9 dBc/Hz at a 10-MHz offset.