Design And Research Of Wideband Miniaturized Antenna Based On Multimode Resonances

With the rapid development and application of the modern communication systems,it is highly demanded for the antennas with miniaturized-size and wide-bandwidth.Low-profile wideband antennas have the wide application prospects in wireless communication systems,such as carrier platforms,satellite communications,and radar systems.In this paper,the microstrip patch antennas(MPAs)and dielectric resonator antennas(DRAs)with low-profile,compact-size,and bandwidth-extension have been deeply studied and analyzed based on the multi-resonant modes.The specific contents are:Firstly,a low-profile wideband MPA under multi-resonant modes is proposed.The antenna has achieved a wide-bandwidth of 25.9%,while keeping a low-profile property with the height of 0.042?₀(?₀ is the free space wavelength at the center frequency).Meanwhile,it holds the stable normal radiation patterns.First,a pair of parallel slots is etched out on the radiating patch and four shorting pins are loaded underneath the patch,so as to make the antenna operating in three resonant modes(TM₃₀,TM₁₂,and TM₁₀ modes).Then,the working principle of the wideband split-ring resonator(SRR)matching network is further studied,and the additional of two non-radiating resonant modes are excited by using a pair of split ring resonators.Finally,the SRR network is successfully combined with the radiating patch.As a result,three resonant modes of the MPA and two resonant modes of the SRR network are merged with each other to effectively extend its impedance bandwidth to about 25.9%,which is about 5.9 times wider than that of the traditional counterpart with the same sizes.Secondly,a novel method for reducing the size of the DRA via the pins is proposed.The antenna has maintained the compact size,wideband,and omnidirectional radiation patterns.In this work,the physical mechanism about impedance bandwidth enhancement of the DRA via the loaded pins is extensively explained.By loading them around the nodal line of electric fields of the TM_01?mode of the DRA,an additional resonant mode could be excited for the antenna with slight influence of its TM_01?mode.As such,the antenna obtains wideband characteristics under dual resonance by properly selecting the size and positions of these pins.Finally,the proposed antenna is fabricated and measured to validate the predicted performances.The results show that the radius and height of the DRA has only maintained of 0.16?₀and 0.09?₀,respectively.Whereas,its impedance bandwidth has enhanced to about 17%(3.65-4.33 GHz)under radiation of dual modes,which is about 3.8 times wider than that of the traditional counterpart with the same sizes.Additionally,it keeps the stable conical radiation patterns.Finally,a novel compact and wideband DRA is designed based on the surface wave band gap characteristics of artificial magnetic conductor(AMC)and the in-phase reflection characteristics of the plane wave.Firstly,the influence of the number and size parameters of the AMC on antenna performance is analyzed.Secondly,in order to realize the wide-bandwidth with the resonance of dual modes,the structure of the AMC is introduced on the top surface of the rectangular DRA,and observing the variation of the electrical properties of the antenna.After that,the antenna size is further reduced by loading the metal conducting plate(the electrical wall).Finally,the impedance-bandwidth of the proposed antenna is broaden to about 17.1%,which is about 8 times wider than that of the traditional counterpart with the same sizes.Meanwhile,the antenna has kept the stable conical radiation patterns with compact size(0.31?₀×0.31?₀×0.045?₀).