Variable Antenna Load for Transmitter Efficiency Improvement

Author

Kaajakari, Ville ; Alastalo, Ari ; Jaakkola, Kaarle ; Seppä, Heikki

Author_Institution

Louisiana Tech Univ., Ruston

Volume

55

Issue

8

fYear

2007

Firstpage

1666

Lastpage

1672

Abstract

A wireless radio transmitter with an integrated variable-impedance antenna is demonstrated. The transmit signal is connected via a switch to the antenna at one of several feed points that correspond to different load impedances that are optimal for the power amplifier at different transmit power levels. It is shown that this can be used to improve the efficiency of the transmission at low and medium transmit powers. The variable antenna load is demonstrated with a planar inverted-F antenna, but the method can be applied to any antenna with suitable impedances.

Keywords

impedance matching; microwave antennas; planar inverted-F antennas; radio transmitters; impedance matching; integrated variable-impedance antenna; microwave communication; planar inverted-F antenna; power amplifier; transmit power level; transmitter efficiency improvement; variable antenna load; wireless radio transmitter; Cellular phones; GSM; Impedance; Loaded antennas; Power amplifiers; Power generation; Radio transmitters; Switches; Transmitting antennas; Voltage; Antennas; impedance matching; microwave communication; power amplifiers (PAs);

fLanguage

English

Journal_Title

Microwave Theory and Techniques, IEEE Transactions on

Publisher

ieee

ISSN

0018-9480

Type

jour

DOI

10.1109/TMTT.2007.902093

Filename

4287170