Antenna Design
M. Zahiry; S. M. Hashemi; J. Ghalibafan
Abstract
Background and Objectives: Printed monopole antenna has an omnidirectional radiation pattern but a narrow impedance bandwidth. To achieve multiband behavior, modification of the antenna shape is necessary. There is no systematic approach for the shape modification and commonly it is done by parametric ...
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Background and Objectives: Printed monopole antenna has an omnidirectional radiation pattern but a narrow impedance bandwidth. To achieve multiband behavior, modification of the antenna shape is necessary. There is no systematic approach for the shape modification and commonly it is done by parametric studies, adjusting, tuning or optimization of an initial shape.Methods: The method for designing a multiband antenna is based on transmission line theory and lumped element model. It applies to all desired multiband operations without needing tuning or optimizing a complex configuration. Every length and dimension are computed from the mathematical formula or Smith chart as a graphical tool. The proposed matching method in the design of a multiband and reconfigurable CPW-fed monopole antenna employed. Both series and parallel impedance matching stubs are investigated and compared with each other.Results: To explain the challenges, the proposed method was applied to a desired antenna. It showed that using matching stubs in the CPW line can design a multiband and reconfigurable antenna. Also, the measurements have been done and compared with the simulations and show a good agreement.Conclusion: Compared to the microstrip line, the CPW feeding of the monopole antenna has the advantage that both parallel and series stubs can be implemented for the matching of the antenna. In this case, the required space for these stubs placed inside the antenna and no extra space needed. So, the printed size of the proposed antenna does not change. The impedance matching method for the integrated stubs with the antenna has been proposed. The high-pass and low-pass properties of each matching network were considered. The authors showed that this method can successfully design multiband, reconfigurable CPW-fed monopole antennas.
Antenna Design
A. Kiani; F. Geran; S. M. Hashemi
Abstract
Background and Objectives: In this paper, a closed-form mathematical formula has been presented using of the proposed periodic structure E-field distribution, that helps designers to calculate the width of the slots in Quasi Non-Uniform Leaky Wave Antenna (QNULWA).Methods: This method is based on two ...
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Background and Objectives: In this paper, a closed-form mathematical formula has been presented using of the proposed periodic structure E-field distribution, that helps designers to calculate the width of the slots in Quasi Non-Uniform Leaky Wave Antenna (QNULWA).Methods: This method is based on two steps. In the first step, some important parameters for the proposed antenna design will be extracted using simulation. In the second step, by solving a discrete differential equation, a general relation will be obtained for these types of antennas. This method has been investigated in the case of slot LWA families. Results: A Leaky wave antenna has been synthesized in the 15.5- 18 GHz frequency range for Gaussian radiation pattern. The results of simulation and antenna design will be very close to each other in 2.5 GHz Bandwidth (15.5 - 18 GHz), which shows the accuracy of this formula. Also, By changing the frequency range 2-5 GHz, the main lobe direction of the antenna will scan the space approximately 10 degrees(from 63 to 73 degree). The antenna has an SLL value of about -25 dB and 13 dB Gain at whole band 15.5-18 GHz .Conclusion: The obtained formula helps the antenna designers to calculate the dimensions this type of antenna for any pattern distribution.
