Wideband Small Microstrip Antenna Substrate Dielectric Material And Structural Studies

Microstrip antennas have the attractive features of low profile, light weight, easy fabrication, and conformability to mounting hosts, that's the reason why microstrip antennas get wide application even if a short history. However, microstrip antennas inherently have a narrow bandwidth, in order to meet the requirement of wireless communication, the bandwidth need to be enhanced. In addition, tradition microstrip antennas structure are big, to satisfy the miniaturization requirements of wireless termination size, compact microstrip antennas are studied. So it is important to study compact and broad band microstrip antennas.In the paper, throughout the study of field between ground plane and patch, the radial characteristic is achieved. Then depict the analysis methods of microstrip, including to transmission line mode, cavity mode, full-wave analysis method and finite element method and so on. Microstrip antenna theory gets development from microstrip circuit, considering the system and devices integration with antennas, the microwave dielectric materials are studied, and details to depict the characteristics and methods of manufacture of BaTiO₃.In the paper, it is important to study the compact and broadband technologies of microstrip antennas. More technologies are analyzed and concluded to obtain compact or broadband microstrip antennas. 90 percent size can be reduced to use meander and short-pin load, it's also a fact that 30 percent bandwidth is obtained to use slot load in patch.Finally, two series of dielectric materials were made according to adulteration and technology, and as substrates to make microstrip antennas. The test results are good, dielectric constant change from 10 to 100.when the dielectric loss is about 0.001, the bandwidth also change from 10MHz to 50MHz according to the different relative permittivity. It can be applied to GPS, RFID and other ceramic antennas, and it also is good to integrate with circuit and microwave devices. To radiate efficiently, an antenna should be built on a thick substrate of low permittivity material, and to get the broadband. Aperture coupling antennas use non-resonate slot to feed, more parameters can be tune, such as the sizes of patches, slot and microstrip, the height of substrate and permittivity and so on. So it's very easy for aperture coupling antennas to get larger bandwidth. If use stacked method, the antennas operate in double frequency band. In this paper, an aperture coupling antenna which operates in Wlan and WiMax is made. As shown in test result, the bandwidth and radio pattern meet well the requirement.