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RSST/R Switch For IMT-2000 Handset Applications
May 2, 2008
Introduction
IMT-2000, International Mobile Technology-2000, is the third-generation technology standard developed by the International Telecommunications Union (ITU) for global mobile communications. The spectrum allocation for IMT-2000 is 1885 - 1980 MHz for uplink (mobile to base station) communications and 2110 - 2170 MHz for downlink (base station to mobile) communication.
In Europe, the system is known as UMTS. The spectrum allocation is 1920 - 1980 MHz (uplink) and 2110 - 2170 MHz (downlink) for Frequency-Division Duplex (FDD) and 1900 - 1920 MHz and 2010 - 2025 MHz for Time Division Duplex (TDD).
Wideband CDMA (WCDMA) is the access technology adapted by major Japanese mobile manufacturers and is incorporated in UMTS.
This article addresses a handset T/R switch design that enables its antennas to be electronically connected to either the transmitter or receiver. It covers both the 1885 - 1980 MHz transmit band (uplink) and the 2110 - 2170 MHz receive band (downlink). Since the T/R switch is placed at the RF front end of the handset, it has significant influence on transmitter efficiency, receiver sensitivity, and battery consumption. An important characteristic of the RF system is transmit signal linearity and purity which strongly affects the level of interference from neighboring channels. The design demonstrates a high-performance T/R switch appropriate for IMT-2000 handset applications utilizing the low-cost SMP1320-079 and SMP1320-017 PIN diodes as switching elements. Click Here To Download:•Application Note: T/R Switch For IMT-2000 Handset Applications
