Neela Chattoraj

Design and analysis of a frequency reconfigurable antenna using metasurface for wireless applications

In this paper a metasurface based frequency reconfigurable antenna is proposed and its design is presented. The design consists of a patch antenna and a metasurface. The metasurface is placed over a patch and is rotated. This changes the equivalent relative permittivity of the structure by which the resonant frequency of the antenna can be tuned. The overall dimension of the antenna is 30 mm with a total thickness of 3.048 mm. The analyzed metasurface acts as a Double Negative (DNG) Material. By using Rogers RO4350B as substrate, antenna resonates from 5.2 to 5.9 GHz. Therefore, the proposed antenna suits for various wireless applications which includes WLAN (5.180 - 5.825 GHz), ISM band (5.725 - 5.875 GHz) and so on. The antenna is designed using HFSS and parameters like return loss, gain, VSWR and radiation pattern are analyzed.

EXPERIMENTAL INVESTIGATIONS ON A SURFACE MICROMACHINED TUNABLE LOW PASS FILTER

In this paper, a surface micromachined microwave tunable low pass fllter, consisting of tunable shunt capacitors and series inductors, has been realized. The fllter exhibits insertion loss of less than 1dB (up to 10GHz), stop band attenuation of 20dB at 20GHz, and cut-ofi frequency is changed to 8GHz with the application of DC actuation voltage in the structure. The fllter has an overall dimension of 5:5mm£2mm. The characteristics of tunable fllter are investigated with and without packaging.

A Compact Novel Tapered U Slot Ultra Wideband Antenna

This paper presents the design and results of a novel, compact and miniaturized tapered U slot UWB printed monopole microstrip antenna for wireless applications. The planar, small and thin UWB antenna fed by a single 50Ω microstrip line with truncated ground plane is excited by a coaxial SMA connector. The correct feed position is determined for impedance matching. The simulation was done using Ansoft High Frequency Structure Simulator (HFSS) software. The simulated results of impedance bandwidth, radiation patterns and group delay are well supported by measurement. Extensive investigations are also carried out on the same antenna design by varying the dimensions to reduce the overall size of the antenna for miniaturization and the UWB performance parameters are studied. The antennas are fabricated and the measured impedance bandwidths defined by VSWR＜2 are 10.34GHz (3.66-14GHz) and 10.60GHz (3.4-14GHz) on FR4 substrate.

Investigation of Electrostatic Actuation Scheme for Low Voltage MEMS Switch

A low voltage MEMS switch based on electrostatic actuation scheme is introduced and investigated thoroughly. Design variables are length, width, thickness of cantilever, and location of pull down electrode, for micro actuator. The model obtained is simulated in FEM-based software COMSOL multiphysics. In our proposed design, the effect of presence of holes, mechanical stress, actuation voltage, and change in location of pull down electrode has been explained. With the help of structural modification and by varying actuation voltage, the optimized value of 8 V is obtained which is desirable for noble performance. The capacitance is varied with the variation of dimensions and gap between two plates of beam structure with applied force, which is the basic principle of electrostatic actuation scheme.

Design and analysis of various Wilkinson Power Divider Networks for L band applications

Different Wilkinson Power Divider Networks using stepped multiple sections of the conventional Wilkinson Divider are presented in this paper. The operating frequency range has been chosen as 1.25 GHz to 1.45 GHz. As, the chosen frequency range lies in the L band, these power dividers can be used as feeding network for antenna arrays operated in the L band. We have fabricated and tested the 2:1, 4:1, 8:1 and 16:1 Wilkinson Power Divider Networks to validate all their simulation results. All these structures have been designed and simulated in CST MWS.

Design of a novel dual: band planar inverted F - antenna for mobile radio applications

The design of a novel compact dual band PIFA (Planar Inverted F-Antenna) as an embedded antenna is reported in this paper for mobile radio applications. The new shorted planar antenna is realized using copper sheet of thickness 1mm and air as the dielectric substrate. The radiating patch consists of a branch line slit to reduce the size of the antenna having a ground size of 36 x 80 mm2. It can be used in internal mobile antennas for applications in GSM band, GCV (1.85 - 1.99GHz), PCS - 1900, IMT-2000 and UMTS 2100 networks. The simulations are done using the Ansoft High Frequency Structure Simulator (HFSS) software tool. The two operating frequency ranges obtained have good matching and radiation characteristics. The simulated results are well supported by measured results of the prototype of the antenna fabricated.

Tetra-Frequency Microstrip Antenna for Wireless Applications

In this paper, the design, fabrication and measurement of a microstrip patch antenna is reported which can be operated at four frequencies – 5.215 GHz, 5.5 GHz, 5.69 GHz and 6.16 GHz. The simulation is done using IE3D software.

A novel CPW fed Sierpinski carpet fractal UWB slot antenna

A Novel coplanar waveguide (CPW) fed Ultra Wideband (UWB) antenna is presented. The proposed antenna is designed on RT/duriod 5880 substrate with thickness of 1.57 mm and relative permittivity of 2.2 having loss tangent 0.0009 using a second iteration Sierpinski carpet fractal with overall dimension of 37 mm × 46 mm × 1.57 mm. The designed antenna offers a good impedance bandwidth from 3.1 to 11 GHz. The presented antenna has omnidirectional radiation pattern and good gain flatness suitable for UWB applications.

Design and analysis of a bandwidth enhanced antenna based on metasurface for wireless applications

Bandwidth enhancement metasurface antenna is proposed in this paper. The structure consists of metasurface as the top layer and patch antenna as the bottom layer. The metasurface consist of array of thirty unit radiating elements. The radiating element is Complementary Split Ring Resonator (CSRR). On increasing the array of unit element the waves coming out from the antenna are affected as a result of which equivalent relative permittivity of the structure changes and so there is change in the bandwidth. The dimension of the metasurface antenna is 38mm × 50mm with a thickness of 3.048mm. The metasurface which is place above the patch antenna is acting like Double Negative (DNG) Material. The metasurface consists of 30 unit cells arranged in a 5×6 layout. Rogers RO4350B is used as substrate for both patch and metasurface, antenna resonates at 5.7 GHz with the bandwidth varying from 70MHz to 140MHz. Therefore, the proposed antennais suitable for WiFiapplication. AnsoftHFSS software is used for designing the metasurface antenna and different parameters like gain, reflection coefficient, radiation pattern and VSWR are analysed.

A Novel Triangular Shaped UWB Fractal Antenna Using Circular Slot

Abstract The article presents the design of triangular shaped fractal based antenna with circular slot for ultra wideband (UWB) application. The antenna is fed using microstrip line and has overall dimension of 24×24×1.6 mm3. The proposed antenna is covering the wide frequency bandwidth of 2.99–11.16 GHz and is achieved using simple fractal based triangular-circular geometries and asymmetrical ground plane. The antenna is designed and parametrical studies are performed using method of moment (MOM) based Full Wave Electromagnetic (EM) software Simulator Zeland IE3D. The prototype of proposed antenna is fabricated and tested to compare the simulated and measured results of various antenna parameters. The antenna has good impedance bandwidth, nearly constant gain and stable radiation pattern. Measured return loss shows fair agreement with simulated one. Also measured group delay variation obtained is less than 1.0 ns, which proves good time domain behavior of the proposed antenna.