Browse Prior Art Database

DUAL BAND RF POWER AMPLIFIERS

IP.com Disclosure Number: IPCOM000008608D
Original Publication Date: 1998-Mar-01
Included in the Prior Art Database: 2002-Jun-26
Document File: 2 page(s) / 79K

Publishing Venue

Motorola

Related People

Gerard Bouisse: AUTHOR

Abstract

Most of the wireless transceivers existing today operate for one standard e.g. GSM, CDMA, NADC and in one RF frequency band. The need for dual band radios is rising and is bringing a new challenge to the RF portion of the radio and more specifically to the RF power amplifier. This amplifier operates in 2 narrow bandwidths separated by an octave or more, e.g. 900MHz and 1800 MHz for GSM and PCN or 835MHz and 1900 MHz for CDMA in US. This paper describes a low cost and simple method of achieving dual band RF power amplifiers.

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MOTOROLA ,Technical Developments

DUAL BAND RF POWER AMPLIFIERS

by Gerard Bouisse

ABSTRACT

  Most of the wireless transceivers existing today operate for one standard e.g. GSM, CDMA, NADC and in one RF frequency band. The need for dual band radios is rising and is bringing a new challenge to the RF portion of the radio and more specifically to the RF power amplifier. This amplifier operates in 2 narrow bandwidths separated by an octave or more, e.g. 900MHz and 1800 MHz for GSM and PCN or 835MHz and 1900 MHz for CDMA in US. This paper describes a low cost and simple method of achieving dual band RF power amplifiers.

PROBLEM

  The bandwidth limitation of a multistage RF power amplifier very often comes from the output matching network (part of the amplifier that sets the performance and where the transformation ratio is the highest). A classical output matching network is based on a 2 section low pass network and features 10% relative bandwidth which tills the need for 2

or 3% relative bandwidth of the existing wireless systems but forbids any dual band operation as described above. For that reason the most popular architecture used for the dual band RF power ampli- fier is the combination of 2 different amplifiers by means of passive network (combiners, duplexers or switches).

This approach is technically valid but costly and requires large areas.

SOLUTION TO THE PROBLEM

Using only one line-up that removes one power amplifier and the combining networks.

  Let's take...