J. A. Ansari

H- Shaped Stacked Patch Antenna for Dual Band Operation

Analysis of U-slot loaded patch stacked with H-shaped parasitic elements is given in this paper. It is found that the antenna exhibits dual resonance and both the resonance frequency (upper and lower) depends directly on slot width and inversely on slot length. Both upper and lower resonance frequency increase with increasing the value of h2. Typically the bandwidth at lower and upper resonance is found 3.66% and 10.25% respectively. The radiated power at higher frequency (beamwidth 64◦) is 0.73 dB as compared to lower resonance frequency (beamwidth 71◦). The theoretical results are compared with the simulated data obtained from IE3D.

ANALYSIS OF A GAP-COUPLED STACKED ANNULAR RING MICROSTRIP ANTENNA

A theoretical analysis of a gap-coupled stacked annular ringmicrostrip antenna with superstrate is performed in order to obtain wider bandwidth operation. The effects of air gap, superstrate thickness and feedingpoint location on the antenna performance are analyzed in TM11 mode usingequivalent circuit concept. It is noted that the proposed antenna is very sensitive to the feedingpoint location in TM11 mode while annular ringmicrostrip patch antenna is independent of feed point in that mode. The optimized proposed antenna shows an impedance bandwidth of 13.96% whereas the antenna without air-gap has 8.75% bandwidth and without superstrate it has bandwidth of 10.89%. The theoretical results are compared with simulated and experimental results.

COMPACT SHORTED MICROSTRIP PATCH ANTENNA FOR DUAL BAND OPERATION

In the present paper notch loaded shorted microstrip patch antenna has been analysed using cavity model. The proposed antenna shows dual band operation which depends on notch dimensions as well as shorting wall. The frequency ratio is found to be 1.5278 for the notch loaded rectangular patch, while in notch loaded shorted patch, the frequency ratio varies from 2.9764 to 2.725 for increasing value of notch width and it is almost invariant with notch depth. Further a slot loaded shorted patch antenna shows the dual frequency nature with the frequency ratio 1.7. The theoretical results are compared with IE3D simulation as well as reported experimental results.

ANALYSIS OF SHORTING PIN LOADED HALF DISK PATCH ANTENNA FOR WIDEBAND OPERATION

In the present paper the analysis of notch loaded shorted half disk patch is given. It is found that the bandwidth of the antenna depends inversely on the notch width whereas it is invariant with the notch length. Further, the antenna shows dual band behavior for a gap spacing below 7.5mm in the gap coupled half disk shorted patch whereas it behaves as a wideband antenna for gap spacing more than 7.5mm. Theoretical results are compared with simulated and experimental results.

E-SHAPED PATCH SYMMETRICALLY LOADED WITH TUNNEL DIODES FOR FREQUENCY AGILE/BROADBAND OPERATION

Analysis of a frequency agile broadband E-shaped patch antenna (ESPA) symmetrically loaded with tunnel diodes is presented in this paper. The notch parameters such as notch-length, notch-width and position are optimized to achieve the optimum broadband operation of ESPA. Under the optimum conditions of ESPA (bandwidth 32.35%), the performance of the antenna is also analyzed as a function of bias voltage of tunnel diode. It may be mentioned that the proposed antenna can be operated in tunable band that varies from 1055 MHz (bandwidth 42.54%) to 1324 MHz (bandwidth 49.77%) with the bias voltage. Further, the radiated power of the proposed antenna is enhanced by 5.67 dB as compared to the E-shaped patch antenna.

HALF U-SLOT LOADED SEMICIRCULAR DISK PATCH ANTENNA FOR GSM MOBILE PHONE AND OPTICAL COMMUNICATIONS

In the present paper, a dual frequency resonance antenna is achieved by introducing half U-shaped slot in semicircular disk. It is analysed by using circuit theory concept. The resonance frequency is found to be 1.50GHz and 2.32GHz, and the bandwidth of the proposed antenna for lower and upper resonance frequency is found to be 5.96% and 11.08% respectively. It is found that the resonance frequency depends inversely on the slot length and feed point, while it increases with increasing the slot width and coaxial probe feed radius. The frequency ratio is found to be 1.54. The theoretical results are compared with IE3D simulation as well as reported experimental results, and they are in good agreement.

Tunnel diode-loaded rectangular microstrip antenna for millimeter range

Theoretical investigations conducted for Ge tunnel diode-integrated rectangular patch antenna reveals that such an antenna exhibits frequency tunability with the bias voltage. The Ge tunnel diode-loaded patch can be operated in the millimeter range (51.042-54.013 GHz). The range of frequency obtainable for operation is 2971 MHz. The radiation pattern shows variation with the bias voltage and the radiated power, the beamwidth and the directivity vary inversely with the bias voltage. Thus, the Ge tunnel diode-loaded patch can be used to achieve electronic tuning (BW=5.66%) with the bias voltage.

Analysis of Microstrip Line Feed Slot Loaded Patch Antenna Using Artificial Neural Network

In this article, the parametric analysis of the slot-loaded microstrip line feed patch antenna is investigated using artiflcial neural network model. The bandwidths of the proposed antenna obtained at TM01, TM02, and TM03 frequency modes are 10.2GHz, 13.6GHz, and 17.2GHz, respectively. The performance of the proposed antenna is analyzed using artiflcial neural network model. The changes obtained in bandwidth due to the position of slot length and slot width are reported. The antenna parameters such as return loss, VSWR, gain and e-ciency are also calculated. The simulated results obtained with the help of IE3D simulation software are trained and tested using ANN. Theoretical results are compared with simulated and experimental ones, and they are in close agreement. Microstrip antennas have sparked interest among researchers because of their attractive features like low proflle, light weight, and conformal to mounting structures, but they have two most serious limitations, narrow bandwidth and low gain (1). Available methods for the analysis of MSA have high level of complexity. Generally, there are two methods for analysis of microstrip antenna such as numerical method and analytical method. The numerical methods is complicated compared to analytical methods and require much more time, whereas, analytical methods are easy and specifled to only some deflnite shapes of microstrip antenna. An artiflcial neural network (ANN) is used here for reducing some of these problems. ANNs are computational tools that learn from experience (training), which provide fast and accurate models for microwave modeling, simulation, and optimization. Using artiflcial neural network microstrip patch antenna was reported by Vegni and Toscano (2) in which they proposed the analysis of MSA using artiflcial neural network. Further, Mishra and Patnaik (3,4) proposed a CAD model for the design of square patch antenna and artiflcial model for efiective dielectric constant of microstrip line. Later, CAD model using spectral domain formulation (5) was also reported for the designing of rectangular patch antenna. Therefore, Guney and Sarikaya (6) proposed a comparative study of MAMDANI and Sugeno fuzzy interface system models for the resonant frequency calculation of rectangular microstrip patch antenna. Several other papers have also used ANN model to analyze and synthesize the microwave circuits (7{15). Thakare and Singhal (16) proposed the analysis of broadband slot-loaded inset feed microstrip patch antenna using ANN model. Most of these papers are based on ANN model presented only simulated and experimental results. In this paper, we provide a theoretical investigation and compare its results with simulated and experimental ones. In this paper, the microstrip line feed slot-loaded patch antenna is proposed. Its theoretical, simulated and ANN results have also been verifled experimentally. The proposed antenna is investigated for triple frequency-band operation, so that single antenna can be utilized for more than one frequency bands. The theoretical analysis of the proposed antenna is discussed using circuit theory concept based on modal expansion cavity model whereas ANN used RBFNN model.

Compact Half U-Slot Loaded Shorted Rectangular Patch Antenna for Broadband Operation

In this paper, analysis of half U-slot loaded patch antenna with shorting wall is presented. The parameters of the antenna signiflcantly depend on slot and notch dimensions. Bandwidth of the proposed antenna is found to be 21.59%. The 3dB beamwidth of the antenna is found to be 90 - at the central frequency of 2.6GHz. The theoretical results are compared with IE3D simulated and experimental ones which are in good agreement.

RBF Neural Network Modeling of Rectangular Microstrip Patch Antenna

In this paper, a design procedure has been proposed for rectangular micro strip patch antenna using artificial neural network, which has been demonstrated using radial basis function neural network. The Neural model was analyzed for 20 sets of input output parameters. The radial basis function outputs are optimized by variation of spread constant and number of neurons. By applying this model we can reduce output error as well as time delay of system. The testing of output of neural model is found in good agreement with theoretical values.