Broadband SOI PA with tunable matching network for improved LTE performances under high VSWR

This paper describes the design of a broadband power amplifier (PA) for LTE PMR handheld applications using a 130nm SOI CMOS technology from ST Microelectronics with high efficiency LDMOS power transistors. The PA has two power modes (3GPP and PMR) and covers the 380–450MHz and 698–862MHz frequency bands thanks to the use of a low-loss SOI Tunable Output Matching Network (TOMN) presenting the optimal load impedance for each power mode and frequency band. The TOMN is used for load tuning purpose and is able to recover any impedance mismatch up to 4:1 VSWR with less than 2dB of insertion loss. The design procedure of the TOMN is detailed in this paper. In 3GPP/PMR modes, the proposed PA provides up to 28.5dBm/31dBm of linear output power in the different frequency bands while keeping an adjacent channel leakage power ratio (ACLR) less than −35dBc with a LTE signal. Corresponding efficiency (PAE) is higher than 35% in the different modes and bands.