G. Shrikanth Reddy

HIGH GAIN AND LOW CROSS-POLAR COMPACT PRINTED ELLIPTICAL MONOPOLE UWB ANTENNA LOADED WITH PARTIAL GROUND AND PARASITIC PATCHES

In this paper a low cost, high gain, low cross-polar and compact edge feed printed elliptical antenna with a partial ground plane and parasitic patches is proposed and investigated. The proposed antenna is fabricated on a 1.6mm thick FR4 substrate with dielectric constant of 4.4 and loss tangent of 0.025. The total planar area of the proposed antenna (L £ W) is 28 £ 24mm 2 . Both the simulated and experimental result shows that the proposed antenna provides a frequency range compatible with the ultra-wideband (UWB) standard, i.e., 3.5GHz{12GHz frequency band. The radiation pattern produced by the proposed antenna is approximately omnidirectional with in- phase excitation of Surface waves resulting in less cross-polarization level (less than 20dB) compared to its co-polar component for the entire impedance band width. The maximum measured gain for the fabricated antenna is around 6.27dBi with an average e-ciency of above 90% throughout the bandwidth. A linear phase response (phase of S21) accompanied by a constant group delay of 1ns throughout the measured bandwidth makes the proposed antenna a good candidate for UWB applications.

Compact Bluetooth/UWB Dual-Band Planar Antenna With Quadruple Band-Notch Characteristics

A compact Bluetooth/Ultrawideband (UWB) dual- band planar antenna with quadruple band-notch characteristics is presented. The proposed structure consists of a UWB semi-elliptical planar monopole, attached to an approximate trapezoidal spiral for 2.45-GHz Bluetooth application. The proposed antenna utilizes rectangular resonant spiral structures for rejection of quadruple frequency bands, i.e., WiMAX (3.3-3.6 GHz), WLAN (5.15-5.35, 5.725-5.825 GHz), and ITU 8 GHz. These resonant spirals are capacitively coupled with the microstrip feedline. The band-notch characteristics are controlled by changing the effective length of the spirals along with coupling gaps between the feedline and the spirals. The proposed antenna also achieves sharp reduction in the gain and efficiency at all the notch frequencies. However , at the passbands, the gain and radiation efficiency are almost stable. A good agreement between the simulated and measured results shows that the proposed antenna with surface dimensions of 24 × 17 mm2 is suitable for Bluetooth/UWB dual-band applications.

Cross-Configured Directional UWB Antennas for Multidirectional Pattern Diversity Characteristics

A cross configuration of directional ultrawideband (UWB) antennas for multidirectional pattern diversity characteristics is presented. Initially, a printed UWB circular monopole having an asymmetric curve shaped CPW feed is designed as a base antenna for obtaining a directional radiation pattern, direction of which remains fairly same for the entire UWB. This base antenna is attached to similar antennas, in a four element cross-configuration to achieve multidirectional pattern diversity characteristics. The proposed structure provides high inter-element isolation of more than 20 dB, with an impedance bandwidth of 19.7 GHz, i.e., 1.3 GHz to 20 GHz. Transmission and diversity characteristics of the proposed antenna are analyzed. Good agreement between simulated and measured results indicates that the proposed antenna is suitable for UWB pattern diversity applications.

Compact printed monopole UWB antenna loaded with non — Concentric open — Ended rings for triple band — Notch characteristic

A compact, ultra-wideband monopole antenna with triple band-notch characteristic is presented. Proposed antenna consists of an elliptical radiator for achieving UWB bandwidth. For rejecting WiMAX (3.3-3.6 GHz) and WLAN (5.15-5.3 GHz, 5.7-5.825 GHz) bands, antenna is loaded with Non-concentric open ended rings. The effective lengths for these non-concentric rings are approximately half wavelength for the respective notch frequencies. Overall surface dimension of the fabricated antenna is 25×18 mm2. The proposed antenna is simulated, fabricated and tested experimentally for its performance. A good agreement between simulated and experimental results ensures the suitability of the proposed antenna for various UWB applications.

Printed band - notched u shaped ultra wide band antenna with modified split ring resonator

This paper presents a band-notched UWB (Ultra Wide Band) Microstrip fed monopole antenna. The band-notch of 5.1 - 5.8 GHz (VSWR >; 2) is easily achieved by inserting dual reverse split ring slots in the radiating monopole of the antenna. By properly adjusting the dimensions of the inserted slot, the proposed antenna revealed good UWB performance i.e. impedance bandwidth of 3 - 10 GHz with VSWR <; 2, accompanied by a band-rejection function (5.1 - 5.8 GHz) in order to avoid interference caused from the IEEE 802.11a band. Time domain response shows that the proposed structure exhibits a minimal and constant group delay (except for notch band) as needed for UWB application. The antenna is fabricated using FR4 (εr= 4.4) substrate having dielectric thickness of 1.59 mm with total size of 30×20mm.

A novel and compact dual band antenna using modified elliptical ring monopole

A novel and compact dual band partial ground coplanar waveguide (CPW) fed monopole modified elliptical antenna design is proposed. Dual band antenna is designed to cover both WLAN band at 2.4 GHz and WiMAX band at 3.5 GHz. Antenna exhibits good return loss characteristics in both the bands. Antenna is designed on RT/Duroid 5880 with dielectric constant 2.2, thickness 1.6 mm and loss tangent 0.0009 to improve the efficiency. Antenna parameters are optimized with respect to dual band characteristics. Based on these optimized parameters antenna prototype is fabricated. Radiation pattern of the proposed antenna is quasi semi-omnidirectional. Parallel agreement between simulated and measured results makes the proposed dual band antenna suitable candidate for modern wireless communication systems.

Compact UWB ring sectoral monopole antenna with dual polarization

A novel, compact and dual polarized ring Sectoral Monopole Antenna (RSMA) with defected ground is presented for Ultra Wide Band (UWB) applications. Present structure has been derived from the circular monopole antenna to accomplish dual polarization characteristics without much change in the impedance band width, radiation pattern (quasi Omni-directional) and other antenna characteristics. Proposed RSMA with partial and defected ground design, UWB response (i.e. 3.1 GHz-10.6 GHz) with reference to VSWR<;2 is achieved. The antenna is fabricated on a RT/Duroid5880 (εr =2.2) substrate having thickness of 0.785 mm with total real-estate of 20×28 mm2. Measurements are in close agreement with the simulated results. Dual polarization characteristics ensure that proposed antenna can be a promising candidate for the UWB applications.

Portable metamaterial inspired directional antenna for underground mine TTE communication

This work presents an implementation of Through-the-Earth two-way voice communication system helpful during the emergency conditions in underground mine. A metamaterial inspired electrically small antenna has been incorporated in our system for system miniaturization and to solve the portability issue without affecting the antenna efficiency and bandwidth. Simulations are done considering the electrical properties of various types of earthy materials to obtain the communication range. The safety limits for electromagnetic radiation hazard are also verified using a male-human body phantom.

Band notch UWB band pass filter with additional GSM 1800 band

Summary form only given. A novel and compact planar ultra wide band (UWB) filter is presented. Stepped impedance resonator (SIR) is used as multimode resonator (MMR). MMR is fed by inter digital coupled lines. Coupled lines are designed such that to ensure low insertion loss over a wide frequency range. SIR (i.e., MMR) produces three resonant modes in the UWB frequency range ensures wide pass band. To avoid the potential interference caused by the co-existing wireless services is mitigated by incorporating band notch characteristics. In addition to UWB pass band, GSM 1800 band for GSM mobile communication with center frequency at 1850MHz is also achieved. Filter exhibits narrow pass band from 1800MHz to 1950MHz and UWB pass band from 3.5 GHz to 10 GHz with reference to 3 dB. At band notch frequency filter exhibits high attenuation level up to 40 dB and ensures less interference caused by co-existing wireless local area network (WLAN) band from 5.6 GHz to 5.9 GHz. GSM 1800 Band is obtained by loading shorted stub to the MMR without disturbing the UWB pass band response. S-parameters of the filter depict good UWB characteristics along with GSM 1800 pass band. Proposed filter is designed based on RT/Duroid 5880 substrate with dielectric constant 2.2 and thickness 0.785 mm. Proposed filter design is aimed to be a compact over reported UWB filter (i.e., surface area of 0.24λ0 × 0.14λ0 (Where λ0 is the free space wavelength at the 6.85 GHz)).

Mutual coupling reduction using shorting posts in UWB MIMO antennas

A multiple input multiple output (MIMO) antenna consisting of two hybrid shaped monopoles for UWB applications is presented. In the proposed antenna, a pair of rectangular strips terminated with shorting posts is used to achieve isolation ≥ 20 dB over UWB. The variations in group delay and transfer-function response are within 1 ns and 13 dB respectively. The envelope correlation coefficient < 0.05 over 3.1–10.6 GHz indicate that the proposed antenna is suitable for UWB MIMO applications.