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Browse Prior Art Database

TWO BAND ANTENNA MATCHING

IP.com Disclosure Number: IPCOM000008938D
Original Publication Date: 1999-Jan-01
Included in the Prior Art Database: 2002-Jul-25
Document File: 2 page(s) / 76K

Publishing Venue

Motorola

Related People

Tal Mor: AUTHOR

Abstract

This paper proposes a simple way of matching narrow band antennae for "wide band" operation, in systems with large duplex spacings.

This text was extracted from a PDF file.
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This is the abbreviated version, containing approximately 52% of the total text.

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MOTOROLA Technical Developments

TWO BAND ANTENNA MATCHING

by Tal Mor

INTRODUCTION

  This paper proposes a simple way of matching narrow band antennae for "wide band" operation, in systems with large duplex spacings.

PROBLEM(S) TO BE SOLVED

  The desire to make small radio communication devices, dictates the use of antennas that are small in relation to the wavelength. Such may include small helix, folded spirals or chip form.

  One of the drawbacks of these antennas is their narrow bandwidth. This is especially emphasized when the frequency allocation for the antenna oper- ation has a large TX to Rx band separation or "duplex spacing."

PROPOSED SOLUTION TO THE PROBLEM(S)

It is proposed that the same switch used for switching between receive and transmit be used for

switching the different matching components. This is especially compatible with radios in which the duplex spacing is large in relation to the antenna bandwidth, but the required receive or transmit bandwidth is within the antenna bandwidth. Thus, the antenna bandwidth, formerly required to be equal to the sum of the Rx or TX band plus the duplex spacing (For example, in the 800 trunked band 19 MHz band (806-825) plus 45 MHz = 64 MHz) may be reduced to the Rx or TX band only (19 MHz in the previous example). Since the anten- na switch will be used in the design to begin with, there is no added cost to the radio in order to achieve the matching (with the exception of a few cheap passive components).

EXAMPLE

  A...