An Electrically Small Inductive-Loaded Planar Antenna
Abstract
It is shown that it is possible to design an electrically small inductive-loaded planar antenna, with a matching post, that is matched to a 50-ohm coaxial line. Planar antennas having a wide range of configurations were simulated at UHF. Many of these antennas performed very well. Three antennas having the best performance were simulated, fabricated and measured. The antennas had shapes that varied from a square of about 5 cm on a side to a low profile shape 3 cm in height and 9 cm in length. The electrical heights of these antennas ranged from 0.055 lambda down to 0.035 lambda. All antennas were elliptically polarized and had simulated maximum gains of about 4.4 dBi along the horizon and about 10 dBi lower at zenith. These antennas are very high Q so the bandwidths were only about 1% for a Voltage Standing Wave ratio (VSWR) below 2.0. The electrical size of the antenna can be further reduced by placing a dielectric slab between the antenna elements. It is shown that it is possible to electrically tune the frequency of the antenna, by placing a variable capacitance in series with the inductance, thus increasing the bandwidth. The agreement of measurements with simulations was excellent.indu
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 25, 2009
- Accession Number
- ADA510475
Entities
People
- Edward Altshuler
Organizations
- Air Force Research Laboratory