Research And Design Of Miniatrue Wideband Or Multi-band Planar Printed Antennas

Nowadays, planar printed antennas are widely needed in the military and commercial applications, because of their low profiles, light weights and convenience in the conformal designs with the carriers, etc. In this thesis, several miniature planar printed antennas with wideband or multi-bands characteristics are proposed, and their electrical performances and structural parameters are fully discussed. The main content of this paper includes the following:1. Research on the planar printed tapered slot antenna loaded by high resistor and shorted pin. A piece of antenna for 1-40GHz with VSWR better than 2.0 is designed and measured. The results show the antenna bandwidth can be broadened and the antenna size can be reduced by 37.4% at least by the novel structure.2. Design of an ultra wideband antenna based on the fringe of the CPW (coplanar waveguide). An M-shaped notch is cut at the bottom of the rectangular patch. The edges of the CPW ground out of the notch follow exponential regularity, and the rest ground in the notch presents T-shape. The input impedance of the antenna is adjusted by the open tapered slot, which is composed of the top of the M-shaped notch and the T-shaped CPW ground. It is proved that the bandwidth of 2.17-24.3GHz, which is about two times of the conventional one, is covered by the novel antenna, and a stable radiation is provided in the whole frequency band.3. Design of a piece of UWB printed rectangular monopole with double widely notched frequency bands. According to the current distributions on the antenna surface, a pair of stubs with the inverted L-shape is loaded at the patch edges and a piece of pentagonal slotline is inserted in the patch. It is shown by the measured and simulated results that the proposed antenna is of good UWB characteristics while rejecting the frequency bands of 3.2-4.25GHz and 5.1-6.15GHz, which cover the application frequency bands of WLAN (Wireless Local Area Network), WiMAX (Worldwide inter-operability for Microwave Access) and the satellite communications at C band.4. Designs of a tri-band printed monopole antenna and an UWB antenna with band rejected characteristics by loading of the stubs, slotline and radial slot on the CPW fed circular patch antenna. The tri-band antenna renders a measured frequency bands of 2.25-2.8GHz,3.3-3.8GHz and 5.1-5.9GHz, which covers WLAN and WiMAX. It is also proved by the measured results that the UWB antenna has band rejected characteristics within the frequency bands of 3.29～4GHz and 5.29-6GHz. A pair of the above two antennas can be used where a high anti-jamming capacity of the antennas is required.5. Research on a new planar double ring resonator and designs of the microstrip patch antennas loaded with such rings. It is proved that the bandwidth of the microstrip antenna can be broadened from 4.7% to 10.5%,15.5%,15.3% and 17.5%, respectively, according to the numbers of the loaded resonator increasing from one to four. A double stacked patch antenna is proposed and designed to further improve radiation characteristic of the antenna with four pieces of rings. The antenna bandwidth can be further broadened to 22.4% with the antenna gain increasing by 2-4dB. The patch antenna with four parasitical rings and the stacked one are, respectively, fabricated and measured. The results validate the wideband designs of the proposed antennas in this paper.