Design Of Compact Multi-Frequency Microstrip Antennas

With the great development of wireless communication, there comes great demand of multi-frequency and broadband antennas of compact size. Microstrip antenna, which has the features of compact size, low profile, small weight, easy to fabricate and able to be integrated with microwave circuits, becomes a good choice.This thesis looks back to the history of microstrip antenna, from when it emerged to when it became popular and widely studied.Then, some classical theoretical methods and popular numerical methods are reviewed. Recent development and some new techniques are also presented in this thesis. An FDTD(Finite Difference Time Domain) example, which is carried out in C++ language, is given to simulate a UWB(Ultra Wide Band) rectangular slot antenna. This program is well demonstrated.At last, several compact multi-frequency antennas are designed and simulated with some professional electromagnetic simulating software. First of all, a novel h-shaped dual-frequency and a modified h-shaped multi-frequency microstrip antenna is proposed and considered to be combinations of microstrip dipoles, which is well demonstrated by good agreement of theoretically predicted, simulated, and measured resonant frequencies. Then, a compact triple-frequency PIFA(Planar Inverted-F Antenna) is proposed for WLAN 2.4/5 GHz and probably Wimax 3.5 GHz band. Simulated and measured results show that these antennas are suitable for current wireless communication systems.