A new design of Microsrtip patch fractal antenna for 2.5 GHz is proposed which possess an excellent size reduction possibility with good radiation performance for wireless applications like Wireless Local Area Network (WLAN). The design and simulation results of Microstrip patch fractal antenna using An soft HFSS is presented which has S11<-10 dB (VSWR<2). The antenna is designed based on the transmission line model with the input impedance of 50 ohm. The fractal geometry for the conventional antenna is generated up to second iteration. The results show that size reduction of 51.9% can be achieved as compared to conventional patch antenna.

This paper presents a novel implementation of an electromagnetically coupled patch antenna using air gap filled substrates to achieve the maximum bandwidth. We also propose an efficient modeling technique using the FDTD method which can substantially reduce the simulation cost for modeling the structure. The simulated results have been compared with measurement to show the broadband behavior of the antenna and the accuracy of the proposed modeling technique. The measured results show a 16% of VSWR<2 bandwidth which is considerable considering the inherent bandwidth limitations in Microstrip antenna technology.

In this paper a circularly polarized single feed patch antenna has been optimized at the frequency of 2.45 GHz. A single stub is used in feed network to make the resonant frequency equal to circularly polarized frequency. Two different patch antennas fabricated on FR4 and RT/Duroid5870 substrates are implemented to investigate the effect of loss on antenna parameters. The measurement results confirm the integrity of simulation results.

In this paper, a wideband high-gain microstip patch array antenna for high resolution synthetic aperture radar applications is presented. The antenna operation frequency is in the X-band and the antenna structure is a four-layer configuration consisting of radiating patches, slots, coupling cavities, and a corporate feeding network, which in turn is fed by a coaxial probe. The increased frequency bandwidth of the radiating patch is achieved by employing a square slot, which appears as a cavity for it, and improves the gain and impedance bandwidth of the antenna array by isolating the patch feeding slot and eliminating the mutual coupling effect. The whole antenna structure is fabricated by using a combination of the milling process and printed circuit technology. Measurement results show a relative gain bandwidth of more than 10%, in which the antenna gain is measured above 28. 8 dBi over the frequency band of more than 1 GHz. Moreover, the relative impedance bandwidth of the antenna for VSWR>2 is more than 16%.

Micro strip circular and square structural ring patch antenna because of most plasticity for receiving an transmitting the signals and also application to driver the active devices are used. An accurate modified wolfe model (MWM) is applied to compute the effective dynamic dielectric constant for determination of resonant frequency micro strip patch antenna circular and square ring without cover. The results obtained from (MWM) have been compared against the result of experimental and other theoretical methods which have very good agreement. Then accuracy of calculated resonant frequency by the (MWM) for dominant mode is about 0.5%. Moreover we calculate the supper strate effect on the resonant frequency dominant and higher order modes of circular and square ring, but the other methods dose not applicable for calculation of the supperstrate effects on the resonant frequency.

A set of hybrid Microstrip patch and semi-circular cavity antennas is introduced. The semi-circular cavity is implemented using Half-mode Substrate Integrated Waveguide (HMSIW) technique. Different shapes of the patch including rectangular, semi-circular and equilateral triangular are excited using proximity effect by the semi-circular SIW cavity at its TM010 mode. The proposed antenna structures have been excited using an inset 50 W Microstrip line that leads to a facility of planar circuit integration. The inherent limited bandwidth of the conventional Microstrip patch antenna and SIW cavity-backed slot antenna is improved about 6 to 10% depending on the type of the patch using the proposed structure. Additionally, the proposed hybrid antenna enhanced the antenna gain by about 1.5 dB in comparison with the half-mode cavity without patch. Meanwhile, the proposed hybrid antennas made on a single-layer substrate has a low fabrication cost using printed circuit board (PCB) process. Three hybrid antennas are numerically and experimentally investigated. A comparative study between the three different structures contains gain, bandwidth, Cross Polarization Level (CPL) and Front to Back Ratio (FBR) is presented.

The finite-difference time-domain (F.D.T.D.) method has applied to the probe-fed rectangular patch Microstrip antenna stacked a parasitic patch for better bandwidth. The input impedance, and the return loss, are calculated and compare with the same results which are derived with the aid of Moment method (Microwave Office 2000). The far field radiation patterns, radiation resistance, and current distribution on the lower patch are calculated with the aid of F.D.T.D. and the mechanism of broadband operation is concluded. It is shown that although a very simple model is used to simulate the coaxial probe-fed in F.D.T.D. simulation, the calculated input impedance and return loss agree well in both of these simulations. The bandwidth is about 10% regarding the relative permittivity (εr=3.38) and the operating frequency (1.2GHz), shows wideband behavior.

This paper describes the design of a 2x2 micro strip patch antenna array in the frequency of 9.5GHz for radar applications, using substrate integrated waveguide, SIW, for feeding network. The micro strip patches are aperture-coupled with the feeding network of SIW. The feeding network consisting of a perpendicular coax-to-SIW transition and two Y-junction power dividers. The antenna is simulated in full wave software of CST and the prototype is fabricated. The measurement results good agreement with the simulation results. a fabricated prototype has a gain of 11.6dB and a side lobe level below -14.5dB in the E-plane and -18dB in the H-plane.

A wide rectangular slot antenna electromagnetically fed by a circular Microstrip patch is proposed. Hybrid Symmetrical Condensed Node in Transmission Line Matrix method (TLM-HSCN) is used to obtain numerical results on the return loss, input impedance and radiation pattern of such antenna structure. Effects of various radiuses of the circular feeding patch and patch position relative to the centre of the slot are considered and their effect on bandwidth is shown.

In this paper theoretical and experimental investigation of a right hand circularly polarized Microstrip rectangular patch antenna have been presented. The antenna has a coaxial feed and designed for operating at L1 frequency (1575 MHz) of global positioning systems (GPS). The antenna have been simulated and optimized using the HP-HFSS software in combination with Empipe3D. The inherently narrow bandwidth of the antenna was increased to 70 MHz using an air layer. A useful practical method was proposed in order to minimizing the input VSWR of the antenna. Theoretical and measured results have been presented and compared.