ACTIVE MICROSTRIP ANTENNAS: INVESTIGATION OF ACTIVE MICROSTRIP ANTENNAS AND IMPROVED PERFORMANCE TECHNIQUES

The microstrip antenna (MSA) is one of the most widely used microwave antennas possessing several advantages. However, it presents a low impedance bandwidth, low gain, and tolerance problems. Probably the most direct way of improving the impedance bandwidth of a microstrip antenna is to attach a separate lossless matching network. The aim of the this study is to develop a new wide band matching systems for improving the electrical characteristics such as, low efficiency, low antenna gain and narrow band. In the research stage of this thesis, different microstrip antenna geometries, matching networks and theoretical models for analysis and design of microstrip antennas were investigated. Three different types of the matching circuits which are realized as the negative capacitance, the negative inductance and the Pi- matching circuit with RC mutator, have been proposed.