An integrated chip-scale active antenna for 5-6 GHz wireless microsystems

An integrated GaAs "chip-scale" microstrip patch antenna with matching power amplifier has been designed. The size of the antenna is ∼4.2 mm × 4.2 mm, which is ∼1/13 of λ₀ at 5-6 GHz. A class A tuned MESFET power amplifier (PA) has been designed with its output matched to the antenna feed point. The antenna is fabricated on the backside of the chip through backside patterning, the PA feeds the antenna through a backside via. The structure is mounted such that the antenna faces up, and is compatible with flip-chip technology. The measurement of a passive (no PA) antenna indicates a gain of -12.7 dB on boresight at 5.64 GHz, consistent with the antenna size reduction. The measurement of the active antenna shows a gain of -4.3 dB on boresight at 5.80 GHz. The active circuitry (PA) contributes ∼8.4 dB gain in the active antenna.