An Active Low-Noise Receiver With Electronic Beamforming Capability at ${ K}_{ a}$ -Band Frequencies

Injection-locked voltage-controlled oscillators (VCOs) are used for a novel implementation of low-noise receivers used for beamforming. A continuous per-receiver phase shift of 400deg is achieved by locking a low-Q VCO and frequency doubling the signal. The used locking circuit and its locking gain are optimized to obtain a large locking range and a continuous phase-tuning characteristic. Phase noise is minimized by developing a high-Q reference oscillator. The achieved low noise figure of only 2.5 dB enables excellent reception of low-power signals. The realization on a RT/Duroid epsivr=10.2 substrate yields a highly compact module, which serves as a testbed for a planned implementation in low-temperature co-fired ceramic technology.