Gijo Augustin

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.

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.

A Quasi-Omnidirectional Antenna for Modern Wireless Communication Gadgets

A compact, planar, wideband antenna designed by modifying the coplanar waveguide is presented in this letter. The proposed antenna finds a wide range of applications including advanced wireless systems (AWS), DCS-1800, DCS-1900/PCS/PHS, WiBro, BlueTooth/WLAN/WiBree/ZigBee, DMB, Global Star Satellite Phones, and digital cordless phones. Wide bandwidth > 75% centered at 2.50 GHz, quasi-omnidirectional radiation coverage along with moderate gain and efficiency are the salient features of the antenna. A prototype fabricated on a substrate with dielectric constant 4.4 and thickness 1.6 mm occupies an area of (31times 64) mm2. Details of antenna design and discussions on the effect of various antenna parameters on the radiation characteristics are presented.

Triple slot arm loaded reconfigurable dual frequency microstrip antenna using varactors

A novel design of a varactor controlled electronically reconfigurable dual frequency microstrip antenna is presented. Dual frequency operation is realized by embedding a hexagonal slot with extended slot arms within a square patch. Varactor diodes integrated with the slot arms are used to tune the operating frequencies considerably, by applying reverse bias voltage. High tuning ranges of 20.75% and 14.36%, respectively, are realized for the two resonant frequencies when the bias voltage is varied from 0 to -30V. This design has the added advantage of up to 69.6% and 50.9% size reduction for the two resonant frequencies compared to the standard rectangular patch. Maximum band widths of 2.1486% and 1.2960% for the two frequencies, with the operating frequency ratios varying in the range 1.2031 to 1.2704, are observed.

Compact dual band antenna for handheld wireless communication gadgets

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.

Meandered slot arm loaded electronically tunable microstrip antenna using varactors

A new design of a compact electronically reconfigurable dual frequency dual polarized single feed, meandered slot loaded microstrip antenna is introduced in this paper. A varactor diode is used to switch the operating frequencies considerably, without much affecting the radiation characteristics and gain. The antenna can work with a frequency ratio varying in a wide range from 1.36 to 1.53. The proposed design has an added advantage of size reduction up to 78% and 49% for the two resonating frequencies, compared to standard rectangular patches. The design also gives considerable bandwidth up to 1.55% and 2.08% for the two operating frequencies

A compact dualband planar antenna for IMT-2000 and WLAN applications

A compact dualband planar antenna developed for IMT-2000 and WLAN applications is presented. The compact planar 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 measured -10 dB band width for returnloss is from 1.91 - 2.34 GHz and 3.21 - 5.58 GHz covering IMT-2000 and WLAN bands. Simulation results along with measurements from the prototyped antenna are presented.

A Novel Leaky Wave Antenna Capable for Electronic Beam Steering

This paper proposes a microstrip slot line leaky-wave antenna, loaded with MIM capacitor, capable of both frequency scannability and fixed frequency beam steering much higher than reported earlier in the band of 4.56 to 5.06 GHz. The proposed antenna design and experimental results are presented

Wide band electronically scannable leaky wave antenna for low cost beam steering applications

In this paper, we present an innovative wide-band, beam steering antenna which is operating in the higher order leaky-mode. The antenna is loaded with log-periodic slots which results a wide bandwidth of 21.36 % over the -10dB resonating band of 4.6 to 5.7 GHz. The pencil beam pattern in the H-plane is frequency scannable over the wide, -10dB band and is also scannable at fixed frequency by reactive loading. A maximum beam steering of about 15/spl deg/ is observed experimentally by changing the loaded reactance from 2.2 pF to 4.7 pF.