Front-to-back ratio

About: Front-to-back ratio is a research topic. Over the lifetime, 292 publications have been published within this topic receiving 3314 citations.

Design of aperture-coupled microstrip antenna for applications in wireless communications

Abstract: In this paper, we describe the design and the experimental implementation of a new aperture-coupled microstrip antenna for broadband applications in wireless systems. Using an aperture-coupled feed method, a rectangular microstrip patch employing a multilayer substrate structure was designed and built. The main motivation of this work was to develop large bandwidth antennas for the PCS band 1850-1990 MHz. The new prototype is characterized by a 10% bandwidth around the center frequency of 1.90 GHz and a low front to back ratio. To examine the performances, numerical results, measurements of S-parameters and radiation patterns are presented.

Beam steering with high front-to-back ratio and high directivity on small platforms using decoupled antenna pairs

Abstract: Beam steering with high front-to-back ratio and high directivity on a small platform is presented. Two closely spaced antenna pairs with eigenmode port decoupling are used as the basic radiating elements. Two orthogonal radiation patterns are obtained for each antenna pair. High front-to-back ratio and high directivity are achieved by combining the two orthogonal radiation patterns. With an infinite ground plane, a simulated front-to-back ratio of 21 dB and a directivity of 9.8 dB can be achieved. Beam steering, at the expense of a slight decrease in directivity, is achieved by placing the two antenna pairs 0.5λ apart. The simulated half power beamwidth is 58°. A prototype is designed and the 2-D radiation patterns are measured. The realized prototype with one-bit phase shifter supports three directions of beam steering. The measured half power beamwidth is 46°, 48°, and 50° for the three respective beam directions. The measured front-to-back ratio in azimuth plane is 8.5 dB, 8.0 dB and 7.6 dB, respectively.

Analysis of characteristics of slot and dipole antennas of georadar

Abstract: Slot antennas and shielded dipole antennas, including resistive material or resistive elements, are considered. Numerical modeling has been carried out by finite difference method in time domain and by integral equation method in frequency domain. The following characteristics has been studied: `front to back' ratio, near field patterns for pulse radiation, far field patterns and energy flux distribution in frequency domain, gain to the ground and the air, input impedance, transient response. An influence of the spacing between the antennas and the ground was studied. Several ways of using of resistive elements and covering were considered: placing of the resistive material into the spacing and around slot antennas, between the dipole and it's screen, including of resistive elements to the bottom surface of the slot antenna, resistive screen of slot antennas. Some optimal antennas have been found. Influence of antenna's design to characteristics is shown. Dipole antenna with a resistive material between the dipole and the screen may provide greater front to back ratio, then the slot antennas, having the same size. Slot antenna with resistive covering on lateral sides ensures high front to back ratio when it is placed on the ground. Optimal conductivity of resistive covering around slot antennas have been found depending of type of the covering and conductivity of the ground.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Design of Substrate Integrated Coaxial Line (SICL) Fed Planar Quasi-Yagi Antenna for Millimeter Wave Application

Abstract: A printed Quasi-Yagi Antenna with a new feed, Substrate Integrated Coaxial Line (SICL) working in the millimeter wave frequency range is presented. This new feeding technique makes the antenna design simple, surpasses the need to have balun and reflector. The antenna design presented here operates at 28GHz with a frequency band of 6.8 GHz, providing a gain of 7.2dBi and front to back ratio of better than 9dB. The SICL section exhibits good shielding ability which is advantageous for circuits implemented in millimeter wave frequency range. It also enhances the performance of the antenna by providing a shielding to feed network. It also reduces the complexity of the feeding network and makes it compact. This antenna is suited for millimeter wave automotive radar application operating at K Band (18–26 GHz).

Wide-beam circularly polarized microstrip antenna with high front-to-back ratio for CNSS application

Abstract: A novel circularly polarized (CP) microstrip antenna with wide beam and high front-to-back ratio is proposed for compass navigation satellite system (CNSS) application. Based on the single-fed patch antenna, parasitic strips are loaded on the same layer to broad the beamwidth. Reactive impedance structure (RIS) is designed as a reflector to obtain a high front-to-back ratio. More importantly, good circularly polarized performance can be obtained in a wider range of beamwidth by adjusting reflection phase. Experimental results show that the measured half-power (HP) beamwidth is approximately 147° and the 3dB axial-ratio (AR) beamwidth is more than 180°. A front-to-back ratio of 20 dB can be achieved within the bandwidth.