A single-layer CPW-FED active patch antenna

A single-layer CPW-fed active patch antenna oscillator at 2.76 GHz is prese nted. The patch antenna acts both as a resonator and a radiator. Electromag netic coupling is utilized for providing the appropriate closed-loop positi ve feedback. The active antenna is built around a commercially available Ga As MMIC on a low-permittivity epsilon(r) = 2.33 Duroid 5870 substrate. The measured effective isotropic radiated power (EIRP) is 20 dBm, whereas the f ront-to-back: ratio is about 12 dB with the cross-polarized fields better t han - 15 dB, The measured phase noise is -87.5 dBc/Hz at a 100-kHz offset a way from the carrier, The structure only requires a single substrate, is co mpatible with uniplanar technology, and results into a low-component count.