A new analytical performance model for cylindrical microstrip printed antenna.

摘要

The fringing field is one of the parameters that have a great effect on the performance of microstrip printed antennas. The fringing field affects the resonance frequency and consequently affects all antenna parameters such as, input impedance, voltage standing wave ratio, return loss, electric and magnetic radiation fields, gain, efficiency, quality factor and bandwidth.;In this thesis we present, a new analytical model for the effect of fringing field on the effective dielectric constant and on the resonance frequency of the microstrip printed antenna. The new model introduces full mathematical expressions for all antenna performance parameters as a function of curvature for a printed microstrip antenna. The model is also used in case of using an array consists of two elements of rectangular microstrip antenna. Mutual coupling coefficient between the elements is also given.;The effect of temperature on a substrate material is presented. Effective dielectric constant and resonance frequency are calculated as a function of curvature and temperature. Hence, all antenna parameters as a function of wide range of temperature and curvature are introduced.;The new model is used to calculate the parameters of a conformal substrate printed on a cylindrical body for TM10 and TM01 mode for a Giga Hertz range, 2.4 GHz and 5 GHz ranges. The substrate materials are RT/duroid-5880 PTFE, K-6098 Teflon/Glass, and Epsilam-10 ceramic-filled Teflon, commercially available substrate, and compare the result for different dielectric constant with the new model. Those materials contained Teflon and or ceramic which mean these materials are flexible so we can use those materials as substrate on conformal microstrip antenna. The dielectric constants for the used materials are 2.2, 2.5 and 10 respectively with a tangent loss 0.0015, 0.002 and 0.0004 respectively. Experimental results would confirm the accuracy of the analytical model.;Furthermore, different antennas designs, their implementation and performance measurements are also presented.