Kushmanda Saurav

A Compact Microstrip-Fed Triple Band-Notched UWB Monopole Antenna

In this letter, a novel low-profile microstrip-fed compact triple band-notched ultrawideband (UWB) antenna is proposed. Notch bands around the 3.3-3.8-GHz WiMAX and 5.15-5.85-GHz WLAN frequencies are obtained by etching out two elliptic single complementary split-ring resonators (ESCSRRs) of different dimensions from the radiating patch of the antenna. Furthermore, by placing two rectangular split-ring resonators near the feedline-patch junction of the antenna, rejection for the 7.9-8.4-GHz X-band frequencies is achieved. Design guidelines for implementing the notch-bands at the desired frequency regions are provided. The match between the simulated and experimental results suggests that the proposed antenna can be a good candidate for application in UWB communication systems.

CRLH Unit-Cell Loaded Multiband Printed Dipole Antenna

In this letter, a conventional single-band printed dipole antenna is loaded with via-less composite right/left-handed (CRLH) unit cells to achieve multiband operation. Symmetrical loading of the unit cells provides a dual-band operation, while the asymmetrical loading of unit cells provides a triple-band operation. The new operational frequencies are lower compared to the resonance frequency of a reference dipole antenna and are controlled by the unit-cell parameters. The radiation patterns at all the operating frequencies of the proposed antennas are omnidirectional. Both the dual- and triple-band prototypes of CRLH loaded dipoles are fabricated to validate the results obtained in simulation. The results of measurements and electromagnetic (EM) simulations are in good agreement.

Dual-Band Circularly Polarized Cavity-Backed Crossed-Dipole Antennas

In this letter, a novel dual-band circularly polarized cavity-backed crossed-dipole antenna is proposed. Complementary split-ring resonators (CSRRs) are loaded along both the arms of double-sided printed crossed dipoles along with vacant quarter-printed rings to achieve dual-band circularly polarized operation. Cavity-backed reflector is employed in the antenna to achieve unidirectional pattern with high front-to-back-lobe ratio ( > 25 dB), wide circularly polarized radiation beamwidth, and high gain in both frequency bands. The impedance and axial-ratio bandwidths in both bands are also considerably improved by the cavity backing. The proposed dual-band crossed-dipole antenna has two operating bands centered at 1.81 GHz (impedance bandwidth 22.4%, axial-ratio bandwidth 6.6%) and 2.67 GHz (impedance bandwidth 33%, axial-ratio bandwidth 10.1%), respectively .

Dual-Polarized Dual-Band Patch Antenna Loaded With Modified Mushroom Unit Cell

In this letter, novel designs of a triple-band linearly polarized patch antenna as well as a dual-band dually polarized patch antenna are proposed. A square slot is etched out along the diagonal of a conventional patch antenna, which is further loaded with a modified mushroom unit cell to achieve a triple-band operation. The lower-order modes are combined to achieve a circularly polarized mode, thus leading to the design of a dual-band dually polarized patch antenna. Both the triple- and dual-band prototypes of a modified mushroom loaded patch are fabricated to validate the results obtained in simulation. The results obtained in both the electromagnetic (EM) simulations and measurements are in good agreement.

Multiband Circularly Polarized Cavity-Backed Crossed Dipole Antenna

In this paper, novel designs of miniaturized and multiband circularly polarized (CP) cavity-backed crossed dipole antennas are proposed. Single-band and dual-band LC resonators are placed along both the arms of double-sided printed dipoles to realize dual-band and tri-band operations, respectively. Identical pairs of loaded dipoles are placed in crossed configuration to achieve dual-band and tri-band CP operations using vacant printed ring. Cavity-backed reflector is further employed to get enhancement in the 10-dB impedance bandwidth (IBW) and 3-dB axial ratio bandwidth (ARBW) along with unidirectional radiation pattern and wide 3-dB axial ratio beamwidth in the operating bands. Measured results confirm that the proposed dual-band cavity-backed crossed dipole antenna exhibits CP operation bandwidths (AR <; 3 dB and S11 <; -10 dB) of 7.50% and 26.15%, with center frequencies at 1.87 and 2.83 GHz, respectively. The corresponding CP operating bandwidths for the tri-band cavity-backed crossed dipole antenna are 1.24%, 9.55%, and 14.95% centered at 1.61, 2.20, and 2.81 GHz, respectively. The proposed dual-band and tri-band antennas can be used in DCS/PCS/Global Star/UMTS/WLAN applications.

A via-less CRLH unit-cell loaded dual-band double-sided printed dipole antenna for GSM/Bluetooth/WLAN applications

In this paper, a conventional single-band double-sided printed dipole antenna is symmetrically loaded with a via-less composite right/left handed (CRLH) unit cell to achieve dual-band operation. The proposed antenna exhibits two frequency bands centered at 1.85 GHz and 2.49 GHz respectively, along with satisfactory peak gain (>1.5 dBi) and dipolar radiation pattern in both the bands. This antenna can be used in GSM, Bluetooth and WLAN applications.

A compact dual band four element MIMO antenna for pattern diversity applications

In this paper, a dual-band four-element MIMO antenna is proposed for PCS/GSM/WLAN/LTE applications. The designed MIMO antenna comprises of L-shaped monopoles loaded with complementary split ring resonators (CSRR) for achieving dual-band antenna characteristics. Good realized gain (>3 dBi) and stable directive radiation pattern is observed in both the working bands of the proposed MIMO antenna. The proposed MIMO antenna exhibits satisfactory diversity performance, as indicated by evaluated MIMO performance metrics like envelope correlation coefficient (ECC), channel capacity loss (CCL) and total active reflection coefficient (TARC). A prototype of the proposed MIMO antenna is fabricated and tested for validation of the proposed concept.

Design of a novel dual band patch antenna loaded with CELC resonator for WLAN/WiMAX applications

A Complementary Electric Field Coupled (CELC) resonator, loaded in the ground plane of a conventional patch antenna to achieve dual band operation is presented here. Two antenna designs have been presented. In the first design, one CELC is etched out from the ground plane of patch antenna which leads to generation of a lower order mode in addition to the conventional patch mode. In order to achieve better impedance bandwidth for the lower order resonant mode two CELC resonators with closely spaced resonant frequencies are etched out from the ground plane of patch antenna in the second design. The proposed antennas can be used in WLAN (Wireless Local Area Network) and WiMAX (Worldwide Interoperability for Microwave Access) applications.

Gain enhancement of microstrip patch antenna using near-zero index metamaterial (NZIM) lens

In this paper, an array of 7 × 7 novel compact metamaterial unit cells is used as superstrate to improve the broadside gain of a microstrip patch antenna operating at the WLAN band. The proposed unit cell is obtained by suitably adding extra metal strips to the conventional mirrored S like structures. The unit cell cell analysis and parameter extraction using periodic boundary condition confirms the near zero index behavior as well as significant reduction (almost 52%) in the unit cell footprint. Simulation and measurement results confirm that near-zero index metamaterial (NZIM) lens significantly improves the gain (by more than 2 dBi) and reduces the half power beamwidth in both E-plane and H-plane by 20°.

Triple band Planar Inverted-F antenna loaded with LC resonator

In this paper, a conventional Planar Inverted-F antenna is loaded with a LC resonator to achieve triple band behavior. The LC resonator enables the excitation of two modes (one lower and one higher) in addition to reference PIFA mode. The radiation patterns at the lower and reference PIFA mode bears the quasi-omnidirectional property while an endfire pattern is achieved for the higher mode. Prototype of the proposed antenna is fabricated to validate the result obtained in simulation.