Small antennas suit FM, UWB bands
By Margery Conner, Technical Editor -- EDN, September 18, 2007
Antennas continue to get smaller and cheaper. For example, Laird Technologies’ miniature Activv internal antenna circuit combines FM, impedance matching, and signal amplification. It replaces the company’s RadioAnt antenna and provides 5-dB greater sensitivity over a frequency range of 76 to 108 MHz in a 25% smaller package. Prices range from 50 cents to $2 (volume quantities), depending on the level of customization.
Omron’s surface-mounted polymeric antenna, the WXA-N2SL, transmits and receives in the 3.1- to 4.9-GHz UWB (ultrawideband) WiMedia Alliance BandGroup 1. The antenna's filter-assistance function suppresses out-of-band noise by 50% or more, enabling high-quality communications between these wireless devices even in noisy environments. The antenna measures 10×13×1.2 mm with a VSWR (voltage-standing-wave ratio) of less than 2.5 in the 3.1- to 4.9-GHz band and greater than 6 in the 7- to 11-GHz band. The linearly polarized device has a feed impedance of 50Ω and sells for approximately $3 (100).
