A 28.5 dBm switched beamforming transmitter for LTE small cell base station application

This paper proposes a RF front-end switched beamforming transmitter for application in LTE small cell base stations. The four element phased array circuit includes passive RC ninety degrees phase shifters, switches and pre-distortion power amplifiers. Each power amplifier can deliver an output power of 23 dBm and a power gain of 26 dB. The proposed transmitter has eight distinct beam directions by employing the proposed array arrangement circuit that compensates for the distance difference caused by constructive interference or destructive wave interference. The circuit was simulated in TSMC 0.18um 1P6M process. The simulated results indicated that the transmitter can generate an output power of 28.5 dBm, a power gain of 17dB and a power added efficiency of 26%.