Radiation Pattern

In this paper, we achieved a very important gain improvement for a circularly polarized (CP) patch antenna using a new left handed medium (LHM) structure. To this end, a homogenization procedure of the LHM is carried out in order to design the patch antenna at a suitable frequency where the losses of the LHM are low. From the results we

Microstrip antennas have a number of useful properties, but one of the serious limitations of these antennas has been their narrow bandwidth characteristic. Efforts to improve the bandwidth usually result in reduction of radiation efficiency and consequently antenna gain. Moreover, its ...

This paper presents the design of a dual band planar inverted F antenna (PIFA) for low orbit satellite applications. The antenna can be used for ground station telemetry communication with the satellite. Two amateur radio frequency bands, 135 MHz and 435 ...

Traditional design guidelines for broadband antenn as do not always produce satisfactory performance for the desired frequency range of inte rest. In addition, the accurate prediction of the f ree- space antenna performance is not sufficient to dete rmine if the antenna will meet a larger system requirement because the performance of the antenna can change significantly when it is

In this paper, an optimal radiation pattern is obtained for a linear antenna array using the particle swarm optimization technique. A set of phase shift weights are generated in order to steer the beam towards any desired direction while keeping nulls in the direction of interferers. The fitness function that allows the calculations of the phase shift weights is presented.

This paper analyses the effect of a central antenna element on the radiation pattern in a uniform circular antenna array. A modification of the array geometry is considered in which one of the antenna elements is placed in the center of the array. The corresponding array factor is adjusted to describe the geometric configuration that includes the central antenna element. This distribution alters the radiation pattern in such a way that the array directivity and half-power beamwidth are affected. An increase on the directivity and a decrease of the half-power beamwidth are obtained by adjusting the phase of the central element. A reduction of the side-lobe levels is also achieved. Array configurations with different number of antenna elements were tested as well, and the results on directivity and half-power beamwidth are presented. Using Microstripes, a software tool that enables the simulation of antennas, a 6-element circular antenna array was designed and the directivity for a ra...

In this paper, a very small 2.45 GHz printed antenna suitable for WLAN application is proposed. In order to decrease the size of the antenna, multi-layer substrate and shorting plate method are used. A microstrip line which can lead to a good impedance matching and four pairs of slot are used to obtain acceptable value of return loss at the

The recently proposed hybrid Green's function method is designed to combine the advantages of both deterministic and stochastic approaches to simulating broadband ground motion when records of small events are not available. The method has the flexibility of incorporating ...

In this paper a method of increasing the bandwidth of a shorted patch antenna is presented. To increase the bandwidth, a tilted parasitic radiator is placed over the driven patch. In spite of this, the height of the antenna remained small and the structure is nearly planar. Measurements confirmed a 44 % bandwidth of the input impedance. In that bandwidth

ABSTRACT A new compact but wideband patch antenna is presented. Compact dimensions are obtained by using a shorted patch. The antenna bandwidth is increased by using a stacked patch configuration. Further increase in bandwidth is obtained by tilting the parasitic patch. The antenna prototype is fabricated and its input impedance and radiation patterns are measured

ABSTRACT A probe station based setup for on-wafer antenna measurements is presented. The setup allows for measurement of return loss and radiation patterns of an on-wafer antenna-hence-forth referred to as the antenna under test (AUT), radiating at broadside and fed through a coplanar waveguide (CPW). It eliminates the need for wafer dicing and custom-built test fixtures with coaxial connectors or waveguide flanges by contacting the AUT with a coplanar microwave probe. In addition, the AUT is probed exactly where it will be connected to a transceiver IC later on, obviating de-embedding of the measured data. Sources of measurement errors are related to calibration, insufficient dynamic range, misalignment, forward scattering from nearby objects, and vibrations. The performance of the setup is demonstrated from 2 to 40 GHz through measurement of an on-wafer electrically small slot antenna (lambda0/35 times lambda0/35,3.5 times 3.5 mm2) radiating at 2.45 GHz and an aperture coupled microstrip antenna (2.4 times 1.7 mm2) radiating at 38 GHz.

This paper presents design and performance analysis of some novel aperture shapes for microstrip reflectarray using patches of variable size. A comparison has been carried out between performance of these novel aperture shapes and some traditional aperture shapes of microstrip reflectarray. For this comparison, first a 29 × 29 center-fed broadside reflectarray is designed and fabricated. Close agreement between simulated and measured radiation patterns confirms the validity of design process. Based on this confirmed design process, reflectarray with different aperture shapes namely reflectarray with diamond-shaped aperture and reflectarray with octagonal aperture has been designed and simulated. From simulated radiation patterns, performance of these reflectarrays has been evaluated and presented.

Abstract A printed circular ring antenna for UWB application is proposed in this paper. The antenna structure is composed of a circular ring patch and a partial ground plane. The proposed antenna has a total size of 39× 40 mm 2. The measurement shows that the ...

This paper deals with the Interference between Fixed Satellite Service Earth Station (FSS-ES) receiver and Fixed Wireless Access (FWA) in term of possible separation distance, for Malaysian environment. The study began with detailed clarification of worldwide regulatory and C-Band user history. Subsequently, detailed calculations of the current and most useful formulas for path loss effect and clutter loss by using

In this paper, a new excitation technique for a printed planar inverted F antenna (PIFA) is described to obtain multi-band operation. In the proposed technique, the printed PIFA is fed from a microstrip line which is coupled to open-end slots in a finite ground. A strong coupling between the microstripline and the ground slots is responsible for generating new resonant frequencies in addition to the one generated by the PIFA element. In contrast to the traditional coaxial probe feed, the use of the microstrip feed allows for coupling to arbitrarily located and orientated ground slots. The advantage of the proposed technique is demonstrated in design examples of multi-band PIFA operating within the 2.4 to 6 GHz frequency band. In the proposed design strategy, the PIFA element of quarter wave length is designed for operation at 2.45 GHz while the location and dimensions of open-ended ground slots are selected to obtain operation at higher frequencies. Two configurations of open-end slots in the ground plane are demonstrated. In the first configuration, an open-end ground slot is chosen to be parallel while in the second configuration the ground slot is selected to be perpendicular with respect to the PIFA element. The multi-band PIFA performance is assessed in terms of return loss, radiation pattern and distribution of surface currents around the primary radiating element and the ground slots at resonant frequencies. The antennas have been fabricated and the experimental results are in good agreement with the simulation.

Abstract A selective modal scheme is proposed to efficiently analyze the problem of high-frequency (HF) electromagnetic (EM) coupling/penetration into or radiation from open-ended waveguides. This scheme is based on the phenomenon that at sufficiently high ...