Ch. Ghobadi

A Novel Design of Reconfigurable Slot Antenna With Switchable Band Notch and Multiresonance Functions for UWB Applications

A novel printed reconfigurable square slot antenna with switchable band-notched and multiresonance performances is designed and manufactured. In the proposed structure, in order to generate single band-notched characteristics, a Π-shaped slot is etched on the radiating stub. Furthermore, to achieve a reconfigurable function, a p-i-n diode is utilized across the slot. When this p-i-n diode is biased forwardly, the Π -shaped slot transforms to a pair of C-shaped slots, and also by changing to this new structure, an additional resonance is excited. Additionally, by cutting two modified L-shaped slits with variable dimensions on the microstrip feed line, new additional resonance is excited, and hence wider impedance bandwidth can be produced, especially at the higher band. The designed antenna has a small size of 20 × 20 mm2 while showing the radiation performance in the frequency band of 3.04 to over 11.17 GHz with a switchable band-rejection performance in the frequency band of 5.03-5.94 GHz. Simulated and experimental results obtained for this antenna show that it exhibits good radiation behavior within the ultrawideband (UWB) frequency range and also it has a reconfigurable frequency band-notched function in the range of 5-6 GHz that can eliminate the interference between UWB frequency band and other existing wireless communication systems.

Dual Band-Notched Square Monopole Antenna for Ultrawideband Applications

This letter proposes a novel printed monopole antenna for ultrawideband applications with dual band-notch function. The antenna consists of a square radiating patch with a pair of L-shaped slits, and an E-shaped slot and a ground plane with a V-shaped protruded strip, which provides a wide usable fractional bandwidth of more than 140% (2.89-17.83 GHz). In order to generate single band-notch characteristics, we use two L-shaped slits in the radiating patch. By adding an E-shaped slot in the center of the radiating patch, a dual band-notch function is achieved. Also, by inserting a V-shaped protruded in the ground plane, additional resonances are excited, and hence much wider impedance bandwidth can be produced, especially at the higher band. The measured results reveal that the presented dual band-notch monopole antenna offers a very wide bandwidth with two notched bands, covering all the 5.2/5.8-GHz WLAN, 3.5/5.5-GHz WiMAX and 4-GHz C-bands. The designed antenna has a small size area of 10 × 16 mm2, which has a size reduction of 35% with respect to the previous similar antenna.

Square Monopole Antenna for UWB Applications With Novel Rod-Shaped Parasitic Structures and Novel V-Shaped Slots in the Ground Plane

A novel band-notched ultrawideband monopole antenna is presented. The proposed antenna consists of a stepped square radiating patch, two rod-shaped parasitic structures for generating band-notched function instead of changing the patch or feeding shapes, and a notched ground plane with two novel V-shaped slots that provide a wide usable bandwidth of more than 200% (3-22.5 GHz). With two rod-shaped parasitic structures, frequency band-stop performance is generated, and characteristics such as band-notch frequency and bandwidth can be controlled. The designed antenna has a small size of 12 × 18 mm2 while showing the band-rejection performance in the frequency band of 5.1/5.9 GHz. The bandwidth of proposed antenna is wider than the bandwidth of antenna in the references.

A Novel Analysis of Minkowski Fractal Microstrip Patch Antenna

Various techniques and geometries have been introduced for size reduction of Microstrip patch antennas, since this class of antennas in spite of inherent application deficiencies; possess preferred benefits in comparison with other choices. This paper presents an evaluation on a novel microstrip patch antenna using Minkowski fractal geometry. Simulation and experimental results indicate efficiency of this technique from the viewpoint of miniaturization for four designed patch antennas by four different depression coefficients. Simulation results are obtained using Ansoft HFSS.

A Novel Band-Notched Planar Monopole Antenna for Ultrawideband Applications

In this letter, a novel planar monopole antenna with a variable frequency band-notch characteristic for ultrawideband (UWB) applications is presented. The UWB property is achieved by embedding two shorted rectangular quarter-wavelength resonators. Two other L-shaped quarter-wavelength resonators coupled to the radiating patch are also used in order to generate the frequency band-stop performance and control antenna characteristics such as band-notch frequency and its bandwidth. The designed antenna has a stopband of 5-5.9 GHz while maintaining wideband performance from 3.1 to 11 GHz with VSWR <; 2.

Design of a Microstrip Slot Antenna Filled by an Isosceles Triangle for UWB Applications

A novel microstrip slot antenna for UWB (Ultra Wideband) antenna applications is proposed. A slot antenna is filled by an isosceles triangle. This structure is fed by a single microstrip line with a fork-like tuning stub. Experiments are carried out to investigate its return loss, its radiation and its time domain behavior, which exhibit good radiation pattern and impedance bandwidth over the entire band of frequency. Time domain consideration also exhibits that this antenna can be used with short pulses.

A Wideband Microstrip-Fed Monopole Antenna for WIBRO, WLAN, DMB and UWB Applications

A small wideband microstrip-fed monopole antenna which consists of a radiating patch with two L-shaped notches and stubs at the lower corners and truncated ground plane, is presented for various mobile communication services such as WiBro, WLAN, DMB, and UWB applications. The proposed antenna is designed to operate over 2.3 to 10.7 GHz for S 11 < −10 dB. In this paper, numerical analysis using Ansoft HFSS and details of the proposed antenna design approach and measured results are also presented and discussed.

Design of a Quasi-Isosceles Triangle Slot Antenna for UWB Applications

A new microstrip slot antenna for UWB (Ultra Wideband) applications is designed. This structure is a quasi-triangle slot antenna fed by a single microstrip line with a fork-like tuning stub. Experiments are carried out to investigate its return loss, its radiation and its time domain behavior, which exhibit good radiation pattern and impedance bandwidth over the entire band of frequency. Time domain consideration also exhibits that this antenna can be used with short pulses.

An ultra-wideband band-pass filter with band-notch performance based on meander embedded open-circuited stub structure

A compact ultra-wideband (UWB) band-pass filter (BPF) with band-notch function is presented in this paper. In the proposed structure defected ground structure (DGS) and four short-circuited bent stubs are used in order to improve the performance of the filter and reduce the size of the filter simultaneously. The upper stop-band with more than 15dB attenuation level extends to 20 GHz. Moreover, a meander-line embedded open-circuited (EOC) stub inside a slot on the main resonator is employed in order to create a narrow band-notch function at WLAN frequencies. The measurement results for the fabricated UWB BPF are in good agreement with simulation predictions and reveals that it satisfies well the demands of the Federal Communications Committee (FCC) with a band-notch function at 5.5 GHz.

A new design of compact dual band-notch UWB BPF based on coupled wave canceller

The procedure of attaining a compact bandpass filter (BPF) with dual band-notch function for ultra-wideband (UWB) applications is presented and discussed in this paper. In the proposed BPF defected ground structure (DGS) is used in order to improve the out-of-band performance of the filter and also four short-circuited bent stubs are employed in order to improve the selectivity of the filter at its cut-off frequencies. Dual band-notch function is added to the performance of the filter by coupling two short-circuited inverted T-shaped stubs to the filter main resonator. The fabricated filter satisfies well the demands of the Federal Communications Committee (FCC) with two narrow band-notch functions at 5.5 GHz and 8 GHz which eliminates the interference of the UWB system with WLAN and satellite communication systems, respectively. The improved upper stop-band of the proposed filter with more than 20dB attenuation level extends up to 20 GHz.