Jinghui Qiu

Research on a Novel Miniaturized Antipodal Vivaldi Antenna With Improved Radiation

A novel antipodal Vivaldi antenna (AVA) is proposed in this letter. The addition of regular slot edges (RSE) helps the antenna lower the low-end operating frequency by 9% with the dimension unaltered, while the radiation patterns at higher frequencies are improved due to the loaded lens and the choke slot edges (CSE) configuration at the termination of the flares, which also contribute to the enhancement of antenna gain. The improved antenna is fabricated and verified experimentally. The measured results coincide with the simulated ones perfectly, which proves the feasibility of the novel design.

Research on a Novel Folded Monopole With Ultrawideband Bandwidth

In this letter, a novel folded monopole antenna with an ultrawideband (UWB) bandwidth and omnidirectional radiation performance has been proposed. An inverted “S”-type structure was formed by folding the planar monopole, which not only realizes dimension reduction, but also contributes to a decrease in the size of the ground plane; the proposed monopole antenna, meanwhile, has a more circular radiation pattern with the frequency ratio of 3.4:1, compared to the planar monopole antenna. Simulation has been carried out together with the measurement of the fabricated antenna. Good agreement between the measured and simulated results can be observed, showing that the antenna is capable of working in the frequency range from 3.1 to 10.6 GHz with return loss less than -10 dB.

DESIGN OF A NOVEL BROADBAND EMC DOUBLE RIDGED GUIDE HORN ANTENNA

An improved double ridged horn antenna (DRHA) is proposed in this paper. By adding the dielectric lens at the aperture of the horn, radiation pattern distortion arising in the high frequency band of conventional DRHA is improved, which leads to higher radiation gain. Meanwhile, ridge slot loading contributes to better impedance matching characteristic, broadening the impedance bandwidth e-ciently. The improved antenna is fabricated and measured, with the measured results consist with the simulation perfectly, which proved the viability of the improvement.

An improved model for the resonant frequency of tunable rectangular microstrip antenna

An improved model for the resonant frequency of a tunable rectangular microstrip antenna is presented. The influence of fringing fields and air gap between the dielectric substrate and ground plate on the resonant frequency is taken into consideration by introducing effective width W/sub eff/ and effective length L/sub eff/, equivalent permittivity /spl epsiv//sub r,equ/ and dynamic permittivity /spl epsiv//sub r,dyn/. The theoretic values are compared with experimental values, showing good agreement.

The design of a novel SBA based on the waveguide feed

The design of Short Backfire Antenna (SBA) based on a waveguide feed and the modification of a sub-reflector is described. It is found that the side-lobe of an antenna with the cone on the sub-reflector can be reduced greatly. Moreover, this structure is good for improving the gain of an antenna. In this paper, in order to satisfy the demand for high power and high frequency, we utilize standard waveguide to feed the antenna. After analyzing a series of parameters that affect the antennas performance, an excellent antenna is given and measured. It can increase the gain by about 0.2/spl sim/0.3 dB and improve the side-lobe.

Effect of design parameters on sidelobe level of short-focus parabolic reflector antenna

In this paper, a low sidelobe short-focus parabolic reflector antenna fed by a half-wave dipole with a disk secondary reflector is presented. Effect of focal length to diameter ratio and secondary reflector parameters on sidelobe level has been explored. Electromagnetic simulations and theoretical analysis of parameters variation were performed. The tendency and degree of the effect of each parameter on sidelobe level have been given. This low sidelobe short-focus parabolic reflector antenna has the advantages of low cost, small size, simple structure and perfect electrical properties. It can be applied to special occasions as life detection radar systems which in need of low cost and small-size.

A novel omnidirectional high-gain microstrip antenna array

In this paper, a novel omnidirectional high-gain microstrip antenna array is analyzed and designed. The series feeding rectangular patch elements are adopted and the combination of two patches of microstrip antenna can realize the 360deg beam overlay of H-plane radiation pattern. This antenna operates at Ku wave band, and the bandwidth can reach 1GHz (S11<- lOdB). The gain is greater than 7.2dB within the operating bandwidth. Measurement results accord with simulation results very well, and the design thoughts can also be applicable for the design of mobile communication base station antenna and WLAN antenna.

A Kind of New Minimize Technology of Circular Polarization Antenna

This paper propose a new kind of circular polarization antenna, i.e. CPA , composed of fold crossed dipole. The fold dipoles are vertical in space, and there is 90 degree phase difference between their feeding current. With the software CST Microwave StudioR , we conclude that there is almost no difference between fold and non-fold crossed dipole about their properties, except their size, the size of fold crossed dipole is about 50% of non-fold crossed dipole.

Novel miniaturized broadband HF antenna

Research on miniaturization of HF antennas is one of the hot research areas. A novel miniaturized broadband HF antenna whose largest size is only 3.6m is presented in this paper. Simulated results demonstrate that the antenna is self-resonant and can be matched to a 50 Ω input feed line without external matching networks or loading in a wide band. The antenna has realized miniaturization while maintaining good performance. It is proposed to be used in shortwave radio communication and other fields with good prospects.

Design and analysis of TEM horn antennas for ultra-wideband technology

TEM horn antennas for ultra wideband (UWB) system applications are proposed in which offer unique advantages by their own structure characters. To realize ultra wideband and high gain operations, some antennas are designed and compared in this paper. By optimization, two classes of antennas can both realize the same radial character, get a satisfied gain and the bandwidth is enough for practical operation. As the UWB antenna, the group delay time is considered specially. The simulation results and analyses at 1-18 GHz frequency band of the TEM horn antenna are presented.