A quad-band 8PSK/GMSK polar transceiver

The paper discusses a first generation polar modulation transceiver system, known as Polaris 2, which has been developed by RF Micro Devices. The transceiver is a digital system which works effectively with digital interfaces. Analog interfaces are also supported for compatibility with older technologies. In Polaris 2, the receiver is composed of two die. The front end part is realized in IBM 5HP SiGe. The use of SiGe technology in this block allows superior sensitivity and intermodulation performance. Four LNAs are included to cover each of the cellular bands (850, 900, 1800, and 1900 MHz). Also included are a mixer, a polyphase filter and a DC correction system. The remainder of the receiver is contained in the main transceiver die which is realized in TSMC 0.25 μm CMOS. The transmit system is the first generation polar modulation transmit system. The large-signal polar modulation transmitter allows the use of an efficient non-linear power amplifier (PA) for both GMSK and 8PSK.