Look Beyond Gain For Mobile Antennas

March 14, 2011
Owing to the increasing use of a variety of wireless networks, gauging antenna performance has become something of a black art. In general, however, antennas are still characterized by basic parameters like efficiency and gain. ...

Owing to the increasing use of a variety of wireless networks, gauging antenna performance has become something of a black art. In general, however, antennas are still characterized by basic parameters like efficiency and gain. Operating-frequency range also must be considered. For certain antennas, the operating frequency partially determines the choice of material for the antenna. In a five-page white paper titled, "Radiated Efficiency: A True Measure of Antenna Performance," Pulse Finland's Jouni Liflnder provides an overview of basic antenna characteristics and their definitions.

For example, one way of measuring antenna performance is with resonance bandwidth. Initially, this bandwidth can be verified with a network analyzer by doing impedance matching. Yet a more accurate antenna-efficiency measurement can be gained by doing the evaluation in an anechoic chamber. In terms of radiated efficiency, Liflnder notes that a good antenna generally will radiate 50 to 60 percent of the energy fed to it (-3 to -2.2 dBi). Even if an antenna has good efficiency, its radiation pattern can have a null in some specific direction or directions.

Gain combines the antenna's efficiency and directivity into one figure, with directivity showing that the antenna radiates with greater efficiency to one particular direction. As a result, gain does not measure the antenna's overall efficiency. Increasingly, the signal emitted from the antenna needs to be equally strong in more than one direction, making gain a poor measure of performance. More companies are therefore choosing radiated efficiency as their preferred test method.

Sponsored Recommendations

Ultra-Low Phase Noise MMIC Amplifier, 6 to 18 GHz

July 12, 2024
Mini-Circuits’ LVA-6183PN+ is a wideband, ultra-low phase noise MMIC amplifier perfect for use with low noise signal sources and in sensitive transceiver chains. This model operates...

Turnkey 1 kW Energy Source & HPA

July 12, 2024
Mini-Circuits’ RFS-2G42G51K0+ is a versatile, new generation amplifier with an integrated signal source, usable in a wide range of industrial, scientific, and medical applications...

SMT Passives to 250W

July 12, 2024
Mini-Circuits’ surface-mount stripline couplers and 90° hybrids cover an operational frequency range of DC to 14.5 GHz. Coupler models feature greater than 2 decades of bandwidth...

Transformers in High-Power SiC FET Applications

June 28, 2024
Discover SiC FETs and the Role of Transformers in High-Voltage Applications