UWB Slot Antenna Research Articles

Compact Cpw‐Fed UWB Slot Antenna with Triple Band‐Notched Characteristics

ABSTRACTA novel compact coplanar waveguide‐fed antenna is presented with triple band‐notched characteristics. A C‐slot is etched in a novel patch to avoid interference from WiMAX band. By using pair of CSRR slots and pair of L‐shaped slits in ground plane, two notched bands for WLAN and ITU 8 GHz bands are obtained, respectively. The antenna has bandwidth of 2.8–11.2 GHz with three notched bands of 3.3–3.7 GHz, 5–6 GHz, and 8–8.4 GHz to avoid interference from WiMAX, WLAN, and ITU 8 GHz bands, respectively. The antenna has good impedance matching and stable radiation patterns. Good agreement is reached between measured and simulated results. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2113–2117, 2013

Design of a Dual Band-Notch UWB Slot Antenna by Means of Simple Parasitic Slits

In this letter, a planar slot antenna with dual-band-notch characteristics is proposed for ultrawideband application. The basic antenna comprises a rectangular tuning stub and a ground plane with a tapered-shape slot. To create a notched band for WiMAX, one angle-shaped parasitic slit is etched out along with the tuning stub, while for WLAN, two symmetrical parasitic slits are placed inside the slot of the ground plane. By properly adjusting the size and location of the parasitic slits, it is found that the proposed antenna can achieve ultrawide operating band with dual-notched band without altering the overall antenna size. These notched bands will help to mitigate the possible interference between UWB and these narrow bands.

Design of a Miniaturization Printed Circular-Slot UWB Antenna by the Half-Cutting Method

In this letter, the miniaturization design of a novel printed circular slot UWB antenna is presented and investigated. By the half-cutting method and adjusting VSWR, the size of the proposed antenna is reduced from 40 × 40 to 10 × 20 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . Experimental results show that the proposed antenna meets the requirement of wide working bandwidth of 3.1-10.6 GHz with VSWR <; 2. Monopole-like radiation pattern is observed in both H-plane and E-plane. The study of transfer function (magnitude and phase of S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</sub> ) and signal waveform indicate a good time-domain characteristic of the antenna. The proposed antenna has a compact size, good radiation characteristics, ultrawide bandwidth, and good time-domain behaviors to satisfy the requirement of the current wireless communication systems.

A CPW-Fed UWB Antenna with C-band/WLAN/X-band Notch Functions using Isosceles Triangular Resonator and Stepped Impedance Resonator

A CPW-fed circular wide slot UWB antenna with C-band, WLAN and X-band notch functions has been presented in this article. The two stop bands are obtained by etching an isosceles triangular resonator with an inner isosceles triangular stub in the circular radiation patch and a stepped impedance resonator with an inner stub in the CPW fed transmission line. The two notched bands can be tuned by changing the dimensions of isosceles triangular, stepped impedance resonator and the inner stubs to give tunable notched band functions. The proposed dual notched band UWB antenna has been designed in details and optimized by means of HFSS. The proposed antenna has a small size of 32x24x1.6mm3. The simulated and measured results show that the designed UWB antenna has an impedance bandwidth of 10.7GHz covering the frequency band from 2.8GHz to 13.5GHz for voltage standing-wave ratio (VSWR) less than 2, except the notch bands 4.0GHz-5.4GHz for C-band and WLAN, 8.2GHz-9.3GHz for X-band which are used in satellite and military communications. The article also refers some recent patents on UWB antenna design. Keywords: Notch band, isosceles triangular resonator, stepped impedance resonator, UWB antenna, ANTENNA STRUCTURE, Impedance bandwidth, designed antennas

A compact UWB slot antenna with signal rejection in 5–6 GHz band

AbstractIn this article, a novel planar slot antenna is presented with band‐notched characteristic for ultra wideband applications.The antenna is fed by coplanar wave guide. A “C” shaped slot etched on the radiating patch to avoid interference from WLAN and HYPERLAN/2 bands. The antenna has measured bandwidth ranging from 3 to 10.6 GHz for VSWR ≤ 2. The antenna has omni directional radiation pattern in H‐plane and bi‐directional in E‐plane. The group delay of antenna is less than 1 ns except in the notched band. Good agreement is found between measured and simulated results. The antenna can be easily integrated with microwave circuitry and is a good for UWB applications. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1292–1296, 2012

Compact reconfigurable UWB antenna integrated with SIRs and switches for multimode wireless communications

A kind of reconfigurable wide slot UWB antenna integrated with stepped impedance resonators (SIRs) and ideal switches is presented. The proposed antenna 1 has dual notch band functions which are obtained by using two stepped impedance stub loaded SIRs. The three reconfigurable models are investigated and discussed. The measurement results with ideals switches demonstrate the performances of proposed reconfigurable antennas. The designed reconfigurable antennas can be suitable for future multi-mode wireless communications systems.

Implementation and investigation of circular slot UWB antenna with dual-band-notched characteristics

The design and analysis of an ultra wideband aperture antenna with dual-band-notched characteristics are presented. The proposed antenna consists of a circular ring exciting stub on the front side and a circular slot on the back ground plane. By utilizing a parasitic strip and a T-shaped stub on the antenna structure, two notched bands of 850 MHz (3.5-4.35 GHz) and 900 MHz (5.05-5.95 GHz) are achieved. The proposed antenna is fabricated and measured. Measured results show that this antenna operates from 2.3 GHz to upper 11 GHz for voltage standing wave ratio less than 2, except two frequency notched bands of 3.5-4.35 and 5.05-5.95 GHz. Moreover, the experimental results show that proposed antenna has stable radiation patterns and constant gain. A conceptual circuit model, which is based on the measured impedance of the proposed antenna, is also shown to investigate the dual-band-notched characteristics.

Confocal Imaging System Using High-Speed Sampling Circuit and Ultra-Wideband Slot Antenna

A low-power impulse-radio ultra-wideband (IR-UWB) confocal imaging system was developed using a low-power complementary metal oxide semiconductor (CMOS) equivalent time sampling circuit and UWB slot antennas. The proposed imaging system uses a Gaussian monocycle pulse with 3 GHz center frequency to detect a target. The sampling circuit is fabricated by 65 nm CMOS technology, and it can achieve a high sampling rate of 28.2 GS/s, input bandwidth of 3.3 GHz and PLL RMS jitter of 3.44 ps with a low power consumption of 50.7 mW. The UWB slot antenna having a 1.53–4.80 GHz input bandwidth is developed for the confocal imaging. An aluminum target was detected using a confocal imaging algorithm.

IMPROVED DUAL BAND-NOTCHED UWB SLOT ANTENNA WITH CONTROLLABLE NOTCHED BANDWIDTHS

A compact dual band-notched ultra-wideband slot antenna with sharp band-notched characteristics and controllable notched bandwidths is presented. The antenna is formed by a rectangular slot with chamfered corners on a printed circuit board ground plane, a T-shaped stub and two sets of compound band- notched structures. The compound band-notched structures are employed to generate desired lower and upper rejected bands with satisfactory skirt characteristics and su-cient rejection bandwidths. Moreover, the bandwidth of either the lower or upper rejected band can be independently adjusted by changing the size and location of the corresponding band-notched structure. Finally, a UWB slot antenna with two rejected bands at WiMAX/WLAN frequencies is successfully simulated, designed, and measured, showing good impedance matching, stable gain and near omnidirectional radiation patterns.

A Multimode Tunable Spherical Wheeler Cap for Broadband Antenna Efficiency Measurements

This paper proposes a simple technique for measuring the radiation efficiency of broadband antennas by using a tunable spherical Wheeler cap made of brass with an inner diameter of 70 mm. The proposed method utilizes a multimode tuner designed as an adjustable brass stub with a ring to compensate the undesirable reductions of the measured efficiency caused by both TM and TE mode resonances of the cap. The required tuning levels for minimizing the undesirable reduction will depend on the Q factors of the cap resonances. The experimental results of a UWB slot antenna, performed at the frequency range of 3 to 10 GHz, show that the efficiency reduction can be minimized by enveloping over all maxima of efficiency curves measured for five different tuner positions.

NOVEL CIRCULAR SLOT UWB ANTENNA WITH DUAL BAND-NOTCHED CHARACTERISTIC

In this paper, a novel circular slot UWB antenna with dual notched frequency band is presented and investigated. A C-shaped slot is inserted into the fed element, and a parasitic strip is printed in the circular slot, so that the proposed antenna achieves dual band- notched characteristics, respectively. The measured and simulated results show that the proposed antenna meets the requirement of wide working bandwidth of 3.1{10.6GHz with VSWR < 2, while avoiding the interference with the 3.5GHz WiMAX and 5.5GHz WLAN band. Study of transfer function (amplitude of S21/group delay) and time domain characteristic (radiated pulses/power spectrum density (PSD)) correspond well with the VSWR, which indicate the dual band notched characteristic of the antenna.

Frequency Notched UWB Slot Antenna with a Fractal-Shaped Slot

A frequency notched ultra-wideband planar slot antenna is presented. By introducing a modified fractal-shaped slot to the patch, a notched band within a wide operation bandwidth is achieved. The designed antenna satisfies the voltage standing wave ratio requirement of less than 2.0 in the frequency band from 3.01 to 13 GHz above while showing the band rejection performance about 500 MHz in the frequency band of 5.59 to 6.09 GHz. Simulation and measurement results are presented for the proposed antenna.

Improved band-notched UWB slot antenna

A compact UWB polygon slot antenna with improved band-notched characteristics using a parasitic strip and a parasitic slit is presented. The antenna has a parasitic strip embedded inside the polygon slot and an isolated slit employed in the bevelled T-stub. The desired excellent band-notched UWB operation can be obtained by choosing the sizes of the parasitic strip and slit. The proposed antenna has a small size of 18×24×0.8×mm, and a nearly omnidirectional radiation pattern, which is suitable for use in various portable UWB antenna applications.

A compact ultra‐wideband slot antenna with multiple notch frequency bands

AbstractA compact printed ultra‐wideband slot antenna with superior multiple band‐notched characteristics is presented. The size of the UWB slot antenna is minimized, and multiple split ring resonators are printed inside the inner patch to achieve multiple notch frequency bands. As a practical example, a UWB antenna (working from 2.4 to 10.1 GHz) etched with two sets of split ring resonators are fabricated and its VSWR and radiation patterns are measured. The measured results agree well with the simulation, and the two notch frequency bands are centered at 3.65 and 5.75 GHz. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 3056–3060, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22892

EM ENERGY ABSORPTION IN THE HUMAN BODY TISSUES DUE TO UWB ANTENNAS

This paper presents electromagnetic energy absorption in the homogeneous and layered human body models due to body-worn UWB antennas, at frequencies of 3, 6 and 8 GHz. Typical small planar UWB antennas are used in this study: printed UWB disc monopole and UWB slot antenna. Distances of 2, 5 and 10 mm (reactive near-field region) between antennas and human body were chosen, approximating realistic scenarios of operation in Wireless Body Area Networks. To approximate different parts of the human body, or body variations among different users, we compare results obtained for the planar homogeneous (muscle) model with those for three-layer body models (skin, fat and muscle), with different thicknesses of the skin (0.5- 2 mm) and fat (1-9 mm) tissue. For these body models we investigate the electromagnetic energy absorption mechanism by examining the peak 1-g SAR and peak SAR (without mass averaging). Based on our results we present and discuss new finding concerning the general electromagnetic energy absorption mechanism in human tissues under reactive near-fields exposure conditions.

Characterization of small planar antennas for UWB mobile terminals

AbstractThis paper presents an extensive investigations to characterize antennas for small UWB mobile terminals. Two small planar UWB antennas (slot antenna and printed monopole antenna) were designed, using a full‐wave electromagnetic finite difference time domain (FDTD) method. The UWB slot antenna has a size of 32 × 29 mm, the monopole antenna size is 20 × 36.75 mm. Both antennas were characterized using true UWB parameters, such as antenna transfer functions, fidelity, and pulse energy spread. We have investigated angular‐dependence of antenna characteristics over the entire radiation sphere. Spatially averaged transfer functions were introduced to disclose antenna characteristics for different solid angles in the radiation sphere. We have also shown the difference in transient characteristics of antenna in transmitting (Tx) and receiving (Rx) mode. Finally, we have investigated the Tx/Rx antenna system, where any relative orientation between Tx and Rx antenna was assumed to be equally probable. Copyright © 2005 John Wiley &amp; Sons, Ltd.