Compact dual band slot loaded circular microstrip antenna with a superstrate

Design of a compact dual frequency microstrip antenna is presented. The structure consists of a slotted circular patch with a dielectric superstrate. The superstrate,not only acts as a radome, but improves the bandwidth and lowers the resonant frequency also. The proposed design provides an overall size reduction of about 60% compared to an unslotted patch along with good efficiency,gain and bandwidth. The polarization planes at the two resonances are orthogonal and can be simultaneously excited using a coaxial feed. Parametric study of this configuration showed that the frequency ratio of the two resonances can be varied from 1.17 to 1.7 enabling its applications in the major wireless communication bands like AWS, DECT,PHS,Wi.Bro, ISM,and DMB. Design equations are also deduced for the proposed antenna and validated.

Circular microstrip antenna with a sector-slot for dual-port operation

Design of a dual-port circular patch antenna with a sector-slot for dual-frequency operation is presented. The antenna resonates at two distinct frequencies with orthogonal polarizations and broad radiation characteristics. Unlike the conventional circular patch, this antenna can be microstrip-fed to operate at either of the resonances. The two polarizations can be simultaneously excited using two electromagnetically coupled ports with an isolation better than −30 dB between the ports. This antenna has the added advantage of size reduction of 44% compared to the conventional circular patch without any reduction in gain.

Broadband dual frequency microstrip antenna

A new dual port microstrip antenna geometry for dual frequency operation is presented. The structure consists of the intersection of two circles of the same radius with their centres displaced by a small fraction of the wavelength . This antenna provides wide impedance bandwidth and excellent isolation between its ports. The gain of the antenna is comparable to that of a standard circular microstrip antenna operating at the same resonant frequency. A theoretical analysis for calculating the resonant frequencies of the two ports is also presented

Single-Feed Dual-Band Circularly Polarised Microstrip Antenna

A novel technique for obtaining dual-hand circular polarization (CP) radiation of a single-feed circular microstrip antenna in proposed and demonstrated. By embedding two pain of arc shaped slots of proper lengths close to the boundary of a circular patch, and protruding one of the arc-shaped slots with a narrow slit, the circular microstrip antenna can perform dual-hand CP radiation using a single probe feed. Details of the antenna design

A new broadband circular patch antenna

A simple technique to improve the impedance bandwidth of a circular microstrip patch antenna using two sectorial slots is proposed. Using this design more than 5% impedance bandwidth is obtained. The added advantage of this new antenna is that it can be fed by a 50- microstrip line

Compact amplifier integrated microstrip antenna

compact microstrip antenna integrated with an amplifier having an area reduction of 70%, compared to the standard circular microstrip patch antenna, is presented. The antenna also provides an enhanced gain of 10-dB more than its passive counter part. The measured 2:1 VSWR band width is -4% at 790 MHz, which is 2.5 times larger than that of the passive microstrip antenna

A New Broadband Circular Patch Antenna

A simple technique to improve the impedance bandwidth of a circular microstrip patch antenna using two sectorial slots is proposed. Using this design more than 5% impedance bandwidth is obtained. The added advantage of this new antenna is that it can be fed by a 50 microstrip line.

Microstrip Antennas For Mobile Telephone Handset With Reduced Radiation Hazards

A novel antenna configuration comprised of two circular microstrip antennas (CMAs) resonating in the TMtt and TM2, modes, producing radiation characteristics suitable for a mobile telephone handset, is presented. The antennas operating at the same frequency are placed back to back with a separation comparable to the thickness of a typical handset. The radiation pattern consists of a region of reduced radiation intensity, which minimizes the radiation hazards to the user

Proceedings Of Eleventh National Symposium On Antennas And Propagation

In this paper we have investigated the effect of cavity diameter and wall height on resonance and radiation characteristics of a circular microstrip patch antenna. Experiments were conducted using a fabricated prototype placed inside a cylindrical cavity. The results were compared and verified with simulated data obtained using an electromagnetic simulator. About 9.6 to 10.5 dBi peak gain was obtained from measured and simulated data

Development and Analysis of Compact AMicrostrip Antennas

The practical applications of microstrip antennas for mobile systems are in portable or pocket-size equipment and in vehicles. Antennas for VHFIUHF handheld portable equipment, such as pagers, portable telephones and transceivers, must naturally be small in size, light in weight and compact in structure. There is a growing tendency for portable equipment to be made smaller and smaller as the demand for personal communication rapidly increases, and the development of very compact hand-held units has become urgent.In this thesis work, main aim is to develop a more and more reduced sized microstrip patch antenna. It is well known that the smaller the antenna size, the lower the antenna efficiency. During the period of work, three different compact circular sided microstrip patches are developed and analysed, which have a significant size reduction compared to standard circular disk antenna (the most compact one of the basic microstrip patch configurations), without much deterioration of its properties like gain, bandwidth and efficiency. In addition to this the interesting results, dual port operation and circular polarization are also observed for some typical designs of these patches. These make the patches suitable for satellite and mobile communication systems.The theoretical investigations are carried out on these compact patches. The empirical relations are developed by modifying the standard equations of rectangular and circular disk microstrip patches, which helps to predict the resonant frequencies easily.

Antenas e superfícies seletivas de freqüência reconfiguráveis para sistemas de comunicação sem fio

This work aims to present how the reconfigurable microstrip antennas and frequency selective surfaces can be used to operate at communication systems that require changing their operation frequency according to system requirements or environmental conditions. The main purpose is to present a reconfigurable circular microstrip antenna using a parasitic ring and a reconfigurable dipole frequency selective surface. Thereupon there are shown fundamental topics like microstrip antennas, PIN diodes and the fundamental theory of reconfigurable antennas and frequency selective surfaces. There are shown the simulations and measurements of the fabricated prototypes and it is done an analysis of some parameters like the bandwidth and radiation pattern, for the antennas, and the transmission characteristics, for the frequency selective surface. Copper strips were used in place of the diodes for proof of the reconfigurability concept

Análise de antenas de microfita com patches circulares sobre substratos anisotrópicos usando o método dos potenciais de Hertz

This work consists on the theoretical and numerical analysis of some properties of circular microstrip patch antennas on isotropic and uniaxial anisotropic substrates. For this purpose, a full wave analysis is performed, using Hertz Vector Potentials method in the Hankel Transform domain. In the numerical analysis, the moment method is also used in order to determine some characteristics of the antenna, such as: resonant frequency and radiation pattern. The definition of Hertz potentials in the Hankel domain is used in association with Maxwell´s equations and the boundary conditions of the structures to obtain the Green´s functions, relating the components of the current density on the patch and the tangential electric field components. Then, the Galerkin method is used to generate a matrix equation whose nontrivial solution is the complex resonant frequency of the structure. In the analysis, a microstrip antenna with only one isotropic dielectric layer is initially considered. For this structure, the effect of using superconductor patches is also analyzed. An analysis of a circular microstrip antenna on an uniaxial anisotropic dielectric layer is performed, using the Hertz vector potentials oriented along the optical axis of the material, that is perpendicular to the microstrip ground plane. Afterwards, the circular microstrip antenna using two uniaxial anisotropic dielectric layers is investigated, considering the particular case in which the inferior layer is filled by air. In this study, numerical results for resonant frequency and radiation pattern for circular microstrip antennas on isotropic and uniaxial anisotropic substrates are presented and compared with measured and calculated results found in the literature

Microstrip circular phased array design and development using microwave antenna CAD tools

The complex design and development of a planar multilayer phased array antenna in microstrip technology can be simplified using two commercially available design tools 1) Ansoft Ensemble and 2) HP-EEsof Touchstone. In the approach presented here, Touchstone is used to design RF switches and phase shifters whose scattering parameters are incorporated in Ensemble simulations using its black box tool. Using this approach, Ensemble is able to fully analyze the performance of radiating and beamforming layers of a phased array prior to its manufacturing. This strategy is demonstrated in a design example of a 12-element linearly-polarized circular phased array operating at L band. A comparison between theoretical and experimental results of the array is demonstrated.

Resonant frequencies of circular-sided dual-port microstrip antenna

A dual-port microstrip antenna with a crescent shaped patch with excellent isolation betwecn the ports has been reportcd [I]. Since circular-sided geometries are inore compact than rectangular oncs, thcy find morc applications in microstrip arrays. The crcscent shaped antenna geometry [ I ] provides greater area rcductioii compared to other circular sided patches for broadband operation [2]. In this Lctter, formulac for calculating thc TM, I and TMZI mode resonant frequencies of this microstrip antenna, obtained by modifying the equations of a standard circular patch [3] are presentcd. Thcorctical results are compared with experimental observations aid the validity of the computation is established.

Compact Circular- Sided Microstrip Antenna for Circular Polarization

Development of a new compact circular-sided microstrip antenna is presented. This antenna offers considerable area re- TABLE 2. Variation of Resonant Frequencies duction compared to standard rectangular microstrip antenna designed for the same frequency. Typical antenna design and experimental results for circular polarization are also demonstrated. 77je antenna has a 3-dB axial ratio bandwidth of 1.5%