Study On The Widening Method Of Frequency Band Of Microstrip Antenna

Microstrip patch antenna is the most typical, frequently used microstrip antenna in modern times. Microstrip antenna has many good characteristics of thin section plane, small volume, easily manufacturing and matching with other shapes easily, easily getting round polarize, bi-frequency band, and bi-polarizes. So they are widely used in many fields such as radar, missile observing and controlling, electronic countermeasure, weapon detonator, remote sensing telemeter measurement, satellite communication, mobile communication, medical microwave, etc. Microstrip patch antenna is a kind of resonance antenna, the characteristic of high-Q resonance determines the high sensitivity of input impedance to frequency change. Compared with other antennas, its frequency band is much thinner, which has become the main obstacle of its extensive use.In order to overcome the limitation of narrow-band of microstrip patch antenna, meet the applied demands of developing wide-band, this thesis mainly introduces the widening technology of the microstrip antenna, and carries on detailed simulation research on the factors which influence the frequency bandwidth of microstrip antenna, explores methods of widening the frequency band of single-layer microstrip patch antenna.This thesis introduces radiation principle of microstrip patch antenna; sets forth four modern analysis methods of microstrip antenna: Transmission Line Model theory(TLM), Cavity Model(CM), law of integral equation, and number value analytical method of the microstrip antenna; and analyzes four important technologies of the widening technology of frequency band: choices of board and patch, impedance match , resistance load and multi-mould.Through these analysis, using XFDTD software, taking three kinds of typical microstrips as examples: rectangle, round, triangle, simulation researches on different materials, different thickness of board, different chinks of board, and different chinks of patch have done. According to the analysis, the thesis explains the different influences to microstrip antenna from dielectric constant, board thickness, geometric shape of patch, chink changes, and comes to the following conclusions:1. Change the relative dielectric constant and thickness of board, the bandwidth ofthe microstrip antenna can be widened, but the relative bandwidth has not exceeded 3%.2. The rational chink load is more effective than the method of changing the relative dielectric constant and the thickness of board, usually the relative bandwidth can be up to 10% to dozens of. 3. Triangle patch is much easier to gain wide frequency band than rectangle and round patch, relative bandwidth is much wider in chink than no chink.4. From the third conclusion, further thought of widening the bandwidth of microstrip antenna by special-shaped patch is put forward.More study will be carried on the widening technology of frequency band of microstrip patch antenna in future work.