In this paper, we propose various defected ground structures (DGS) for improving the return loss and impedance bandwidth of an ultra wideband antenna. A comparative parametric analysis has been made on the basis of return loss, gain, radiation pattern characteristics and impedance bandwidth. Simulation results are analyzed and presented for an ultra wideband antenna with four slots in its radia...

A CPW-fed ultra-wideband antenna was designed. The antenna was etched on a single-layer copper-cladding substrate, of which the material was FR4 with relative permittivity of 4.4, and the magnitude was 40.0 mm × 50.0 mm × 1.6 mm. The parameters of the antenna are simulated and optimized with HFSS. This paper proposes a new trapezoidal CPW-fed UWB antenna that the bandwidth (return loss ≤ −10 dB...

Introduction: Annular ring slot antennas are considered to be among the narrowband resonant antennas and occupy an area of l=4p at their first resonance [1]. Multi-element concentric ring slots have been used to design multi-band antennas [2]. However, because of transmission zeros that exist between the different resonances, these resonances cannot easily be merged to obtain a wideband respons...

A compact printed ultra wideband (UWB) monopole antenna with multi-notched characteristics is presented. By inserting multiple E-shaped slot in micro strip feed line and ground plane, additional resonances are excited. The multi notch has been created by embedding a pair of – L shaped arm in the radiating patch and a modified E-slot defected ground structure in the feeding line. The designed an...

This study presents a theoretical design study of a novel three-dimensional micromachined hemispherical shell antenna for ultra-wideband millimetre-wave imaging applications. The antenna is composed of a hemispherical metallic shell which is suspended on top of a high-resistivity silicon substrate using a thin silicon stem. The antenna exhibits two different operational modes and an exceptional...

In this paper a wideband dual polarized antenna is designed, manufactured and measured. Slot coupled patch antenna structure is considered in order to achieve the wideband characteristic. Although rectangular shaped slot coupled patch antennas are widely used in most of the applications, their utilization in dual polarized antenna structures is not feasible due to space limitation. For a rectan...

─ A novel loop-loaded printed dipole (LLPD) with a wideband balun structure is presented for aiming a dual-band antenna operation at 3.0/5.5 GHz bands. The proposed balun structure alone demonstrates VSWR<1.5 performance over a 3:1 bandwidth. As the loop elements placed on the antenna aperture provides dual-band operation with at least 15% impedance bandwidths, the wideband balun/feed allows fo...

A novel twin-diamond-shaped antenna is presented for wideband circularly polarized (CP) radiation. By introducing a twin-diamond-shaped patch and a gap-coupled feed structure, a lefthanded circularly polarized (LHCP) antenna in bore-sight direction is obtained. The gap-coupled feed structure consists of a horizontal microstrip arm of approximately 0.285λ0 at the centre frequency and two small d...

Computation of the broadband matching potential of a microstrip antenna requires the wideband lumped equivalent circuit of the antenna. The general topology of the equivalent circuit of rectangular microstrip patch antennas has been used to model the feedpoint impedance of microstrip antennas over a wide frequency band and equivalent circuit parameters are determined using optimization techniqu...

In this paper, we introduce a new compact dual-polarized conformal slot antenna fed by two orthogonal Coplanar Waveguide (CPW) semi-discs. To achieve a high isolation between the two ports, a strip is inserted diagonally in the ground plane. The simulations are done using the Computer Simulation Technology (CST) Microwave Studio software. The simulated results show that the proposed antenna pro...