Antenna to Antenna Isolation

Antenna to antenna isolation is a measure of how tightly coupled antennas are. Typically, antenna isolation is measured for antennas on the same product - that is, the isolation between a smartphone gps and wifi antenna, for instance. When specified in this manner, the isolation should be as large as possible. Isolation between a GPS and WIFI antenna that are near each other will be on the order of 20-30 dB, with higher values being preferred. The method of measuring isolation is typically done by connecting both antennas to a Vector Network Analyzer, and measuring S12 (the transmission coefficient). For antennas that share a common ground plane, such as the diversity and primary cellular antennas on a smartphone, the isolation can be as low as -10 dB or less at the lowband. This will cause a loss in both antenna's efficiency. Antenna to antenna isolation can be increased by: Increasing the physical separation between the antennas Using different polarizations for the antennas in question If the antennas have different frequencies, using filters to reduce efficiency at the opposite antenna's frequency Reducing the correlation coefficient between the antenna's radiation patterns - that is, have the antenna's peak radiation in different or opposite directions Antenna Definitions List Antennas (Home) This page on antenna isolation is copyrighted. No portion should be reproduced electronically without the permission of the webmaster. Copyright antenna-theory.com, 2013.