Broadband microstrip antennas

Microstrip antennas are inherently narrow band. The typical bandwidth of a microstrip antenna is around 4%-7%. A considerable number of experimental approaches have been undertaken to develop microstrip antennas which have a broader impedance bandwidth than a single microstrip element achieves without external matching. The methods employed to increase impedance bandwidth are essentially variations of three approaches: (a) Increasing the antenna volume. This is accomplished by geometry changes which increase the volume under the patch (e.g. increasing the thickness h), decreasing the substrate dielectric constant, or adding additional coupled resonators. (b) The implementation of a matching network. (c)…