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Browse Prior Art Database

REFLECTOR DIVERSITY ANTENNA

IP.com Disclosure Number: IPCOM000005482D
Original Publication Date: 1983-Mar-01
Included in the Prior Art Database: 2001-Oct-08
Document File: 1 page(s) / 49K

Publishing Venue

Motorola

Related People

James P. Phillips: AUTHOR [+2]

Abstract

Radio communication in the UHF range is degraded by signal fading causedCQmultiple reflection from adjacent buildings and surroundings. To improve performance and provide a quiet and clean signal in the presence of fading, a receiver is usually equipped with some form of diversity. The reflec- tor diversity antenna is a very low cost method of implementing a two branch switched diversity into a radio receiver.

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'xi, MOTOROLA Technlcal Developments Volume 3 March 1983

REFLECTOR DIVERSITY ANTENNA

By James P. Phillips and Henry L. Kazecki

   Radio communication in the UHF range is degraded by signal fading causedCQmultiple reflection from adjacent buildings and surroundings. To improve performance and provide a quiet and clean signal in the presence of fading, a receiver is usually equipped with some form of diversity. The reflec- tor diversity antenna is a very low cost method of implementing a two branch switched diversity into a radio receiver.

   The proposed diversity technique consists of two X12 dipole antennas in close proximity (A/4) to one another (see attached figure). The first main antenna is connected directly to the radio receiver and the second is either open or short circuited by a switch and thus acts as a switchable parasitic reflector. When the switch is open the reflector has a small scattering area and thus interacts very little and the first antenna operates unaffected. During times when the switch is closed, the second antenna is reso- nant and is a large scatterer which couples energy into the first antenna. In some conditions when the first antenna is in a deep fade and the second is not, closing the switch will scatter power into the main receiver antenna. A PIN diode as a switch allows automatic control of the antenna by electronic cir- cuitry. This switching action reduces the probability of deep fades in the received signal and as a result the perfo...