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.

Simple approach to determine resonant frequencies of microstrip antennas

A simple approach for accurate determination of the resonant frequencies of microstrip antennas of regular geometries is developed and presented. In this approach, a generalised empirical formula for the computation of effective dielectric permittivity is given which takes into account the ratio of the fringing area to the area of the patch. A correction to the equivalent side length of an equilateral triangular patch, previously published, is modified and a new formula is given. A correction to the effective dimensions of an elliptical microstrip antenna is also carried out. Numerical results obtained for the resonant frequencies of elliptical, circular, rectangular and equilateral-triangular microstrip antennas are in good agreement with the available theoretical and experimental results reported by others. The present approach is more efficient, simpler and more accurate

Resonance Frequencies of Compact Microstrip Antenna

The arrow shaped microstrip antenna, which produces dual frequency dual polarisation operation with considera-ble size reduction compared to conventional patches has been reported [I]. These antennas provide greater area reduction and improved gain compared to drum shaped patches [2]. Prediction of the resonance frequency of drum shaped patches [3] and circular patches for broadband operation [4] are available in the literature. In this Letter, we propose empirical formulas for calculating the resonance frequencies of the arrow shaped microstrip antenna. These antennas can be employed for obtaining dual frequency with the same polarisation, bandwidth enhancement, circular polarisation etc. by varying its different parameters or by introducing slots. The proposed design equations provide an easier and simple way of predicting the resonant frequencies of these patches.

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

Dual-band dual-polarized compact microstrip antenna

Experimental studies on a compact dual frequency microstrip antenna are presented. This antenna configuration provides an area reduction of 40% compared to a standard rectangular antenna operating at the same frequency without much degradation of the gain. The antenna structure can be modified to achieve the desired ratio between the two resonant frequencies

Analytical Equations for Compact Dual Frequency Microstrip Antenna

Design equations are presented for calculating the resonance frequencies for a compact dual frequency arrow-shaped microstrip antenna. This provides a fast and simple way to predict the resonant frequencies of the antenna. The antenna is also analyzed using the IE3D simulation package. The theoretical predictions are found to be very close to the IE3D results and thus establish the validity of the design formulae

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%

Dual-Port Dual-Polarized Microstrip Antenna

Experimental and simulated results for a dual-port dual-polarized microstrip antenna are presented. The antenna excites two orthogonally polarized resonant frequencies providing an isolation of -30 dB between the ports. The patch geometry consists of two circular arcs of different radii with their centers displaced by a distance. This new design offers an area reduction of -70% coinpared to it standard rectangular microstrip antenna with a reduction in gain of 1.7 dB

Analysis and Design of a Dual-Port Compact Microstrip Antenna

A dual-port dual-polarized compact microstrip antenna for avoiding cross coupling between the two frequency bands is proposed and analyzed. This antenna offers channel isolation better than 25 dB, and is more compact compared to a conventional rectangular patch. Analytical equations for calculating the resonant frequencies at both ports are also presented. The theoretical calculations are verified using experimental results

Dual-frequency dual-polarized slot -coupled compact microstrip antenna for communication system

A new design of' a dual-frequency dual-polarized square microsh'ip antenna fed along the diagonal, embedded with a square slot having three extended stubs for frequency tuning, is introduced. The proposed antenna was fabricated using a standard photolithographic method and the antenna was tested using the HP 3510(:; Vector Network Analyser. The antenna is capable of generating dual resonant frequencies with mutually perpendicular polarizations and broad radiation pattern characteristics. Such dual-frequency designs find wide applications in personal mobile handsets combining GSM and CDS 1800 modes, and applications in which different frequencies are used for emission and reception such as personal satellite communications and cellular network systems.

A Compact Novel Slot-Loaded Dual-Frequency H-Shaped Antenna

A novel compact single-layer dual frequency microstrip antenna which uses an H-shaped geometry with two U-shaped slots embedded near the radiation edges, is presented. By changing the design parameters, the lower and higher resonant frequencies can be controlled easily, and a range of frequency ratios (1.716-2.363) can be obtained in this design. For the two operating frequencies of the proposed antenna, the same polarization planes and broadside radiation patterns are achieved. Compared to the regular dualfrequency patch antenna, this antenna can realize a significant size reduction

Development of a varactor -controlled dual-frequency reconfigurable microstrip antenna

A new design for a compact electronically reconffgurable singlefeed dual frequency dual-polarized operation of a square-microstrip antenna capable of achieving tunable frequency ratios in the range 1.1 to 1.37 is proposed and experimentally studied. Varactor diodes inlegruted with the arms of the hexagonal slot and embedded in the square patch are used to tune the operating frequencies by applying reverse-bias voltage. The design has the advantage of size reduction up to 73.21% and 49.86% for the two resonant frequencies, respectively, as compared to standard rectangular patches. The antenna offers good bandwidth of 5.74% and 5.36% for the two operating frequencies. A highly simplified tuning circuitry without any transmission lines adds to the compactness of the design

Design of Compact Reconfigurable Dual Frequency Microstrip Antennas Using Varactor Diodes

The design of a compact, single feed, dual frequency dual polarized and electronically reconfigurable microstrip antenna is presented in this paper. A square patch loaded with a hexagonal slot having extended slot arms constitutes the fundamental structure of the antenna. The tuning of the two resonant frequencies is realized by varying the effective electrical length of the slot arms by embedding varactor diodes across the slots. A high tuning range of 34.43% (1.037–1.394 GHz) and 9.27% (1.359–1.485 GHz) is achieved for the two operating frequencies respectively, when the bias voltage is varied from 0 to −30 V. The salient feature of this design is that it uses no matching networks even though the resonant frequencies are tuned in a wide range with good matching below −10 dB. The antenna has an added advantage of size reduction up to 80.11% and 65.69% for the two operating frequencies compared to conventional rectangular patches.

C-shaped slot loaded reconfigurable microstrip antenna

A new electronically reconfigurable dual frequency microstrip patch antenna with highly simplified varactor tuning circuitry is presented. The proposed design allows relatively independent selection of the two operating frequencies. Tuning ranges of 7.1 and 4.1% are realised for the two resonant frequencies without the use of any matching circuits.

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.