Babau R. Vishvakarma

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.

Gap-coupled microstrip array antenna for wide-band operation

The theoretical and experimental investigations carried out on a gap-coupled microstrip array antenna reveal that there is a significant improvement in VSWR and bandwidth characteristics of the gap-coupled microstrip array antenna as compared with a conventional microstrip array antenna. The input impedance and the resonant frequency of the gap-coupled patch are found to depend heavily on the gap length as well as on the dielectric constant of the substrate material.

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.

Analysis of Gunn integrated annular ring microstrip antenna

The analysis conducted on Gunn integrated annular ring microstrip antenna and evaluation of various parameters such as input impedance, voltage standing-wave radio voltage standing wave ratio (VSWR), return loss, bandwidth, radiation pattern, beamwidth, etc., as a function of bias voltage and threshold voltage reveals that the Gunn loaded patch offers wider tunability, better matching, enhanced radiated power as compared to the patch alone. Bandwidth of the Gunn loaded patch improves to 11.07% over the 7.9% bandwidth of the patch whereas the radiated power is enhanced by 3.7 dB as compared to the patch.

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.

Design considerations for the development of the annular ring microstrip antenna

The design considerations for development of the annular ring microstrip antenna are considered and consequently various parameters such as input impedance, VSWR, return loss and radiation pattern have been theoretically investigated as a function of frequency for different feed locations with a view to optimizing the feed location for proper matching and radiation. It has been observed that resonance occurs at 3.285 GHz, which is invariant with feed location. The antenna behaves as an RL network below resonance and as an RC network above resonance and shows perfect matching at a feed location of 3.35 cm from the centre. The percentage bandwidth is found to decrease and radiated power to increase with increasing ratio of outer to inner radius of the ring antenna.

Analysis of gap-coupled microstrip antenna

In the present paper the analysis of a gap-coupled microstrip antenna (GCMSA) is carried out using the circuit concept and consequently various parameters such as input impedance, VSWR and return-loss are investigated for different air gap lengths. It is observed that the resonant frequency of the antenna with different substrates depends on the gap length. The gap-coupled antenna behaves as an RL network below the resonant frequency for all substrate materials and gap lengths, whereas the antenna behaviour above resonance is like an RC network. It is further observed that the resonant frequency of the GCMSA decreases with increasing gap length.

Analysis of electromagnetically coupled two-layer elliptical microstrip stacked antennas

Theoretical analysis of a coaxially fed, electromagnetically coupled two-layer elliptical microstrip stacked antenna based on circuit theory is presented in which mutual coupling is considered. Consequently, various parameters such as input impedance, VSWR, return loss, bandwidth etc. are investigated as a function of frequency, which shows resonance at 3.0GHz. It is also observed that there exists a critical value of frequency (3.0GHz) below which capacitive coupling is dominant and above which inductive coupling is dominant. The electromagnetic coupling enhances the radiated power which depends directly on the permittivity of the substrate, in spite of the fact that radiated power generally decreases with increasing permittivity of the substrate.