A compact wideband antenna place above a non-uniform artificial magnetic conductor (AMC) is presented. The antenna is composed of a wideband coplanar waveguide fed antenna, with wideband harmonic suppression characteristic using non-uniform defected ground structure. Besides, a non-uniform wideband AMC is designed. The AMC unit cell is composed of a square patch into which a four arms spiral shape is etched. It exhibits a wider ±90°bandwidth than the spiral unit cell and a smaller size than the square patch unit cell. The antenna is placed above the proposed AMC structure formed by 6 9 5 unit cells. The overall dimensions of the complete structure are 0.7 9 0.6 k 0 2 , where k 0 is the free-space wavelength at the lowest frequency. It offers a low-profile configuration with a total thickness of k 0 /14.3, and it is matched between 2.5 and 5.4 GHz (73.5 %). Furthermore, it has a stable main lobe radiation pattern in the E-and H-planes within the operating frequency band. Moreover, compared with the antenna without AMC, the broadside realized gain is significantly increased. A prototype has been realized, and there is a good agreement between simulated and measured results. Furthermore, the proposed structure presents a size reduction of about 34 %, and better radiation characteristics in comparison with the conventional square AMC.

both E-plane and H-plane which is by far the standard. The bandwidth covers 2. 365-2.475 GHz at À10 dB return loss condition. CONCLUSIONThe development and performance of a 2 by 4 element linear polarization suspended microstrip patch antenna array is described. The array design is based on a low cross-polarization suppression technique. The analysis of cross-polarization suppression techniques in linear arrays reveals that, even though some particular structures can cancel these fields efficiently, the geometrical composition of the entire array affects the SLLs. This work presents a novel technique. Using this technique the cross-polarization level on the array is significantly suppressed compared to the cross-polarization level of the basic radiating element and no undesired side lobes occur in the radiation pattern of the array. ACKNOWLEDGMENTSThis work was supported by SEMCAD X by SPEAG. www.speag.com ABSTRACT: This article presents a coplanar waveguide-fed wideband bowtie antenna with harmonic suppression using non-uniform cascaded defected ground structure units. The antenna operates between 2 GHz and 5.4 GHz and harmonics are effectively reduced. Its size is only 0.44Â0.48 k 0 2 , k 0 being the free-space wavelength at 2 GHz. Simulation and measurement agree very well. V C 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:829-835, 2013; View this article online at wileyonlinelibrary.com.ABSTRACT: A broadband left-handed (LH) waveguide operating above the cutoff frequency is presented. The unit cell consists of oneshorted stub and two-twisted posts. The structure induces double loops in the surface currents, resulting in enhanced inductance which broadens the negative permeability region. To analyze the LH properties of the structure, a 2-port network cross-connected equivalent circuit is derived. The measured results of the LH waveguide constructed with five unit cells in an X-band are in good agreement with simulated data and show a good transmission property as well as a broad LH fractional bandwidth of 26.5%. V C 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:835-840, 2013; View this article online at wileyonlinelibrary.com.

In this paper we present the design of a CPW-fed wideband bow-tie antenna with harmonic suppression using three non-uniform cascaded bow-tie DGS (defected ground structure) units. The total size of the antenna is 66x73mm 2 (0.44x0.48λ 0 2 , where λ 0 is the free-space wavelength at the lowest operating frequency). DGS dimensions are optimized to suppress the second and the third harmonics bands. The proposed antenna is matched between 2 GHz and 5.4 GHz (92%), and the band between 7 GHz and 22 GHz (103.5%) is rejected. The antenna has an omnidirectional dipole-type radiation pattern over the whole frequency band.