Research On Dielectricresonatorantenna And Microstrip Patch Antenna With Small Size And High Gain

With the rapid modern wireless communication development, new base station antennas have become one of the most important research focuses in contemporary antenna engineering. Dielectric resonator and patch antennas have many attractive features in terms of low profile, light weight, simple coupling and ease of fabrication. This dissertation presents the novel design and implementation of compact and high gain dielectric resonator antennas and low profile patch antennas. Three major subjects are outlined as follow:1. A compact wideband hybrid dielectric resonator antenna is proposed. The proposed antenna utilizes a combination of a rectangular dielectric resonator and a micro-strip fed rectangular shaped coupling slot, and two metallic patches. By adding an air layer between the dielectric resonator and the metallic patches, additional resonances close to that of the dielectric resonator antenna are obtained, resulting in a broadband response. The measured-10 dB return loss bandwidth is 25.6％(1.7-2.2 GHz). The measured antenna gains are about 6.3 and 8dBi in the operating frequency band. A low cross-polarization level of less than-26 dB is achieved. Moreover, the overall dimensions of the antenna are only 67×67×34(mm3).2. Wideband folded V-shaped patch antenna element and its array are proposed. The proposed antenna is composed of a folded V-shaped patch, an H-shaped coupling slot cut in the ground plane and a feed line with a stub printed on the bottom layer of the grounded substrate. By folding the V-shaped metallic patch, the proposed antenna can achieve a low profile structure and good performance in radiation patterns. The prototypes with the single element can achieve a-lOdB return loss bandwidth of 28.5％(1.65 to 2.2GHz) and a stable gain of 8.6dBi, while the 1×2 array exhibits a bandwidth of 34.1％(1.58 to 2.23GHz) and a stable gain of 11.5dBi.3. Probe-fed dual U-slot patch antenna element and its array are proposed. The antenna element is made by cutting two symmetrical U-slots in a single layer patch. The feeding probe used in this antenna is composed of two metal probes with different sizes of radius. The micro-strip feed line printed on the upper side of the substrate is connected to the patch through the feeding probe. The prototypes with the single element can achieve an impedance bandwidth (VSWR<2) of 42.4%(1.71 to 2.63GHz) and a peak gain of 8.1dBi, while the 2×2 array exhibits an impedance bandwidth (VSWR<2) of 26.5％(1.7 to 2.22GHz) and a peak gain of 14dBi. The height of antenna array is only 0.1λo (where is the free-space wavelength referring to the center frequency of the working band). The cross-polarization level is less than-20 dB within the 3-dB beam widths.