A Coplanar Waveguide Fed Hexagonal Shape Ultra Wide Band Antenna with WiMAX and WLAN Band Rejection

In this paper, a coplanar waveguide (CPW) fed hexagonal shape planar antenna has been considered for ultra-wide band (UWB). This antenna is then modified to obtain dual band rejection. The Wireless Local Area Network (WLAN) and Wireless Microwave Access (WiMAX) band rejections are realized by symmetrically incorporating a pair of L-shape slots within the ground plane as well as a couple of I-shape stubs inserted on the bottom side of radiating patch. The proposed antenna has stop bands of 5.05-5.92 GHz and 3.19-3.7 GHz while maintaining the wideband performance from 2.88 - 13.71 GHz with reflection coefficient of ≤ -10 dB. The antenna exhibits satisfactory omni-directional radiation characteristics throughout its operating band. The peak gain varies from 2 dB to 6 dB in the entire UWB frequency regions except at the notch bands. Surface current distributions are used to analyze the effects of the L-slot and I-shape stub. The measured group delay has small variation within the operating band except notch bands and hence the proposed antenna may be suitable for UWB applications

Implementation and Investigation of a Compact Circular Wide Slot UWB Antenna with Dual Notched Band Characteristics using Stepped Impedance Resonators

A coplanar waveguide (CPW) fed ultra-wideband (UWB) antenna with dual notched band characteristics is presented in this paper. The circular wide slot and circular radiation patch are utilized to broaden the impedance bandwidth of the UWB antenna. The dual notched band functions are achieved by employing two stepped impedance resonators (SIRs) which etched on the circular radiation patch and CPW excitation line, respectively. The two notched bands can be controlled by adjusting the dimensions of the two stepped impedance resonators which give tunable notched band functions. The proposed dual notched band UWB antenna has been designed in details and optimized by means of HFSS. Experimental and numerical results show that the proposed antenna with compact size of 32 × 24 mm2, has an impedance bandwidth range from 2.8 GHz to 13.5 Hz for voltage standing-wave ratio (VSWR) less than 2, except the notch bands 5.0 GHz - 6.2 GHz for HIPERLAN/2 and IEEE 802.11a (5.1 GHz - 5.9 GHz) and 8.0 GHz - 9.3 GHz for satellite and military applications

A Tri-band-notched UWB Antenna with Low Mutual Coupling between the Band-notched Structures

A compact printed U-shape ultra-wideband (UWB) antenna with triple band-notched characteristics is presented. The proposed antenna, with compact size of 24×33 mm2, yields an impedance bandwidth of 2.8-12GHz for VSWR<2, except the notched bands. The notched bands are realized by introducing two different types of slots. Two C-shape half-wavelength slots are etched on the radiating patch to obtain two notched bands in 3.3-3.7GHz for WiMAX and 7.25-7.75GHz for downlink of X-band satellite communication systems. In order to minimize the mutual coupling between the band-notched structures, the middle notched band in 5-6GHz for WLAN is achieved by using a U-slot defected ground structure. The parametric study is carried out to understand the mutual coupling. Surface current distributions and equivalent circuit are used to illustrate the notched mechanism. The performance of this antenna both by simulation and by experiment indicates that the proposed antenna is suitable and a good candidate for UWB applications

A novel SWB antenna with triple band-notches based on elliptical slot and rectangular split ring resonators

In this paper, a wideband antenna was designed for super-wideband (SWB) applications. The proposed antenna was fed with a rectangular tapered microstrip feed line, which operated over a SWB frequency range (1.42 GHz to 50 GHz). The antenna was implemented at a compact size with electrical dimensions of 0.16 ¿ × 0.27 ¿ × 0.0047 ¿ mm3, where ¿ was with respect to the lowest resonance frequency. The proposed antenna prototype was fabricated on a F4B substrate, which had a permittivity of 2.65 and 1 mm thickness. The SWB antenna exhibited an impedance bandwidth of 189% and a bandwidth ratio of 35.2:1. Additionally, the proposed antenna design exhibited three band notch characteristics that were necessary to eradicate interference from WLAN, WiMAX, and X bands in the SWB range. One notch was achieved by etching an elliptical split ring resonator (ESRR) in the radiator and the other two notches were achieved by placing rectangular split ring resonators close to the signal line. The first notch was tuned by incorporating a varactor diode into the ESRR. The prototype was experimentally validated with, with notch and without notch characteristics for SWB applications. The experimental results showed good agreement with simulated results.Postprint (published version

Polarization Diversity UWB Antennas with and without Notched Bands

Acknowledgement to The Electromagnetics AcademyIn this article, a couple of UWB antennas are presented. These antennas have the shape of two overlapped circles. The presented antennas are polarization diversity antennas with and without dual band reject filters. Measurements show that the antennas work well within the whole UWB. Antennas have practical reflection parameters S11 and S22 lower than −10 dB, practical coupling parameters S12 and S21 lower than −15 dB, an Envelope Correlation Coefficient lower than 0.015 and a diversity gain between 9.97 to 9.99 dB. Simulations of the antennas are done using the CST softwar

Novel Dual Band Frequency Selective Surface and its Applications on the Gain Improvements of Compact UWB Monopole Antenna

In this work, a highly directional ultra-wideband (UWB) microstrip patch antenna as a single-element is suggested. The proposed antenna’s gain is enhanced with a novel dual-band frequency selective surface (FSS) placed beneath it. The FSS design has a hexagonal structure with meander line inductances and a capacitance-like structure connecting all of the corners to the middle. There is no metallic layer on the other side of the substrate, which shows transmission zeros at 4.95 GHz and 12.7 GHz, and a modified U-shaped monopole antenna is developed. First, the performance characteristics of the antenna and FSS are analyzed from the simulation results, and they are validated experimentally after fabrication, followed by measurement. The compact configuration comprises an antenna loaded with the proposed FSS results S11 less than -10 dB from 3.15 GHz to 22.65 GHz, covering the UWB band together with the X, Ku-band with a bandwidth of 19.5 GHz (151.16% FBW). The antenna’s overall physical dimensions would be 38.8 mm×38.8 mm×25.2 mm (0.407λo×0.407λo×0.265λo), with λo denoting the lowest frequency’s free-space wavelength. The FSS loading results in a 9.9 dBi maximum gain at 10 GHz. The antenna’s small size increases bandwidth, and its high peak gain makes it ideal for use in real-time applications

A CPW-Fed Novel Planar Ultra-Wideband Antenna with a Band-Notch Characteristic

A coplanar waveguide (CPW) fed novel planar ultra-wideband antenna with a band-notch characteristic is presented. The proposed antenna consists of a rectangular metal radiation patch and a tapered arc-shaped ground plane. To achieve ultra wideband, three modifications are introduced, the first one is to remove a 90-degree fan angle on the upper corners of the patch, the second one is to shape the bottom of the patch into an arc, and the third modification is to remove a small fan angle on each side of the ground plane near the feeding line. Simulation results show that the proposed antenna operates over 3.0 to 23 GHz for VSWR < 2. By embedding a C-shaped slot in the radiating patch, a frequency band notch between the bandwidth of 5 to 6 GHz for Wireless LAN (WLAN) will be obtained. All simulations in this work were carried out by using the electromagnetic software Ansoft HFSS 11. Compared with the recently proposed antennas, this antenna has advantages in wide bandwidth, good band-notch characteristic, compact in size and easy design. Details of the proposed antenna are presented, and simulated results show that the antenna has stable radiation patterns and good gain flatness over its whole frequency band