V. P. Sarin

An Electronically Reconfigurable Microstrip Antenna With Switchable Slots for Polarization Diversity

An electronically reconfigurable microstrip antenna with circular and linear polarization switching is presented. The prototype fabricated on a substrate of dielectric constant (εr) 4.4 and height (h) 1.6 mm is fed by a proximity feed fabricated using the same substrate. By controlling the bias voltage of two PIN diodes, the polarization of the antenna can be switched between three states; two states for linear polarization (horizontal and vertical) and one state for circular polarization (RHCP). Simulation and experimental results show that the proposed antenna has a cross polar level better than 10 dB in the linear polarization state and 18 MHz axial ratio bandwidth in the circular polarization state. The frequency and polarization diversities of this design could potentially improve the reliability of wireless communication systems.

A Compact Dual-Band Planar Antenna for DCS-1900/PCS/PHS, WCDMA/IMT-2000, and WLAN Applications

A compact dual-band planar antenna developed for DCS-1900/PCS/PHS, WCDMA/IMT-2000, and WLAN applications is presented. The proposed antenna consists of a flared monopole with an additional sleeve for dual-band applications. The overall size of the antenna is 40 mm times 25 mm times 1.6 mm including the Finite Ground CPW feeding mechanism. The antenna operates in two frequency bands from 1.83 to 2.34 GHz and 3.23 to 5.76 GHz covering DCS-1900/PCS/PHS, WCDMA/IMT-2000, and WLAN bands. Simulation results along with measurements of the prototyped antenna are presented and discussed.

Wideband Printed Microstrip Antenna for Wireless Communications

A simple electromagnetically coupled wideband printed microstrip antenna having a 2:1 VSWR bandwidth of 38% covering the 5.2/5.8-GHz WLAN, HIPERLAN2, and HiSWANa communication bands is presented. The large bandwidth is obtained by adding a rectangular metal strip on a slotted square microstrip antenna. The antenna occupies an overall dimension of 42 times 55 times 3.2 mm3 when printed on a substrate of dielectric constant 4. It exhibits good radiation characteristics and moderate gain in the entire operating band. Details of the design along with experimental and simulation results are presented and discussed.

A Wideband Stacked Offset Microstrip Antenna With Improved Gain and Low Cross Polarization

A broadband printed microstrip antenna having cross polarization level >; 15 dB with improved gain in the entire frequency band is presented. Principle of stacking is implemented on a strip loaded slotted broadband patch antenna for enhancing the gain without affecting the broadband impedance matching characteristics and offsetting the position of the upper patch excites a lower resonance which enhances the bandwidth further. The antenna has a dimension of 42 × 55 × 4.8 mm3 when printed on a substrate of dielectric constant 4.2 and has a 2:1 VSWR bandwidth of 34.9%. The antenna exhibits a peak gain of 8.07 dBi and a good front to back ratio better than 12 dB is observed throughout the entire operating band. Simulated and experimental reflection characteristics of the antenna with and without stacking along with offset variation studies, radiation patterns and gain of the final antenna are presented.

A Broadband

A broadband <;i>;L<;/i>; -strip fed printed microstrip antenna is presented. The strip loaded slotted broadband microstrip antenna is fed by an L-strip feed line to achieve impedance matching for the higher order modes of the patch antenna in addition to the existing resonances. The antenna offers 74% bandwidth when printed on a substrate of dielectric constant 4.2 and has an overall dimension of 42 × 55 × 3.2 mm3. The simulated and experimental reflection characteristics of the antenna with and without the L-feed along with radiation patterns, input impedance variations, gain and efficiency of the final antenna are presented and discussed. The time domain transient analysis indicates a minimum dispersion to the transmitted pulse.

L

A tilted slotted microstrip antenna incorporating dual band dual polarization is proposed. The antenna is operating in the WLAN 5.2 GHz/5.8 GHz bands having bandwidth of 7.32% and 3.28% respectively in the first and second bands.The peak gain of the antenna is found to be 3 dBi for the first band and 4 dBi for the second band.

-Strip Fed Printed Microstrip Antenna

A novel compact dual frequency reconfigurable microstrip antenna achieving polarization tuning by loading a single chip capacitor is presented. A cross shaped patch antenna with an X-slot 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 with an embedded capacitor at the centre of the X-slot. A high tuning range of 34.48% (672– 952MHz) and 14.3% (1.5145–1.748GHz) is achieved for the first and third resonant frequencies respectively while minimizing variations of the second resonant frequency. Measured and simulated results of the antenna indicate that the frequency ratio can assume any value in the range 1.025 ≤ fR ≤ 1.21 with linear or circularly polarized radiation by changing the capacitor value from 1pF to 100pF. Furthermore, the proposed antenna offers moderate gain with low cross-polarized radiation and the radiation patterns of each frequency remain unchanged as the capacitor value is changed.

A dual band dual polarized microstrip antenna for WLAN applications.

A compact dualband monopole antenna covering DCS-1900/PCS/PHS, WCDMA/IMT-2000 and WLAN bands is proposed. Various parameters of the antenna are optimized through simulation and prototyped the optimized geometry. Measured VSWR bandwidths are observed to be 24.5% (1.83-2.34 GHz) and 56.3% (3.23-5.76 GHz) in the first and second resonant bands respectively. The proposed antenna provides nearly omnidirectional radiation characteristics with moderate gain and efficiency which is suitable for the new generation communication gadgets.

Frequency and polarization tuning of a cross patch antenna using capacitive loading

A novel compact truncated ground monopole quasi Yagi antenna for enhanced gain performance is proposed. Gain enhancement is achieved by implementing asymmetric feeding technique on a coplanar wave guide fed monopole antenna. The peculiarity of this design is that it utilizes the reflecting property of the truncated ground plane of the asymmetric coplanar wave guide fed monopole antenna. The design achieves a good front to back ratio greater than 10 dB and the maximum gain achieved by the antenna is found to be 5.76 dBi.

Compact dual band antenna for handheld wireless communication gadgets

A simple electromagnetically coupled wide band printed microstrip antenna having a 2∶1 VSWR bandwidth of 38% covering the 5.2/5.8 GHz WLAN, HIPERLAN2 and HiSWANa communication bands is presented. The large bandwidth is obtained by adding a rectangular metal strip on a slotted square microstrip antenna. The antenna occupies an overall dimension of 42 × 55 × 3.2 mm3 when printed on a substrate of dielectric constant 4. It exhibits good radiation characteristics and moderate gain in the entire operating band. Details of the design along with experimental and simulation results are presented and discussed.