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Antenna Principles
Published in Jerry C. Whitaker, The RF Transmission Systems Handbook, 2017
Pingjuan L. Werner, Anthony J. Ferraro, Douglas H. Werner
Input impedance, which is measured at the feeding point of the driver, is affected by the reflector and directors due to the mutual coupling effect. The amount of effect on resistance and reactance on the driven element by the parasitic depends on the spacing and the length of the elements. A good front-to-back ratio gives maximum forward signal and minimum rearward signal. Normally, the best front-to-back ratio can not be obtained without sacrificing the maximum gain. An optimum design, which gives a maximum front-to-back ratio with a small sacrifice in gain, is obtainable by proper adjustment of the spacing and length of Yagi elements.
Pattern Diversity Antennas for Base Stations
Published in Shiban Kishen Koul, G. S. Karthikeya, Millimetre Wave Antennas for 5G Mobile Terminals and Base Stations, 2020
Shiban Kishen Koul, G. S. Karthikeya
The radiation patterns in H-plane (YZ) and E-plane (XY) at 28 and 30 GHz are depicted in Figure 5.4. The beamwidth in the H-plane is 65° ± 5° for the entire band, indicating high pattern stability. The front-to-back ratio is more than 10 dB. Similarly, the beamwidth in the E-plane is 35° ± 5°, with a front-to-back ratio of 13 dB, because of the electrically larger ground plane.
Design and Developments of UWB Antennas
Published in Chinmoy Saha, Jawad Y. Siddiqui, Yahia M.M. Antar, Multifunctional Ultrawideband Antennas, 2019
Chinmoy Saha, Jawad Y. Siddiqui, Yahia M.M. Antar
The front-to-back ratio (f/b) is a parameter describing the directional radiation patterns for antennas. If an antenna has maximum gain in a particular direction, the front-to-back ratio is the ratio of the maximum gain in that particular direction to the gain in the opposite (180 degrees) direction. The parameter is given in dB.
Analysis and Design of a Dual-polarized Printed Monopole Antenna
Published in IETE Journal of Research, 2021
In this paper, a low-return loss dual-polarized monopole antenna has been designed using the PCB technology. We considered the joint design of the monopoles and the feed grounds with a chamber which is well calculated and optimized. This joint design greatly improves the port matching and the isolation between two ports. The feeding structure is composed of two F-type feed lines and two corresponding feed grounds with a chamber, which are printed on the front and the back of the FR4 substrate, respectively. The proposed antenna consists of two mutual vertical printed monopoles with an area of 25 × 15 and 35 × 15 mm2, respectively. And the two square monopoles generate vertical and horizontal polarization separately. A circular reflective ground plane is applied under the substrate. The front-to-back ratio performance of the pattern is enhanced, and the gain of the antenna is also better improved by adding the reflective ground plane. The simulations and the experiments have been carried out for the proposed antenna agreeing well with each other. Measured results of the fabricated antenna show that the 10 dB return loss bandwidth of two ports both cover the frequency band of 1.081–1.158 GHz, and a ports isolation better than 20 dB has been achieved. In section II the design and the optimization of the proposed antenna are given. In section III, the simulated and the measured results are presented. Finally, we summarize this paper in section IV. The full-wave EM simulator CST Microwave Studio is used for design, simulate and parameter optimization in this paper.