Azzeddin Naghar

Single notched-band UWB antenna for WLAN environment using complementary split ring resonators CSRR and spiral resonator CSR

Ultra-wide band (UWB) technology has become more popular due to various applications such as ground penetrating radar, medical imaging and sensor networks. The antenna is one of the key components of UWB systems and has drawn much attention in recent years. In this paper we propose the design of UWB monopole antenna, providing single notched-band for WLAN (5–6) GHz to avoid interference signals, using complementary split ring resonators CSRR and spiral resonator CSR. It consists of a microstrip patch with modified radiating element and ground plane, while the desired notch-band characteristic is achieved by etching separately CSRR and SCR in the radiating patch, in Fig.1. Investigations on the parameters of the CSRR were performed to obtain the same performance of CSR in high frequency keeping away it second resonance. Fig.2 shows simulated and measured return loss of proposed single notched-band UWB monopole antennas, compared to the antenna without filtering property. It can be seen that the monopole antenna covers the whole UWB band (3–11 GHz) with a good rejection of WLAN band for notched-band antennas. Also a good response is observed in high frequency of UWB band. for the antennas gain, it varies between 3dBi and 5 dBi. From it performances, The proposed antennas are a good candidate for UWB applications where notch-band for WLAN is required. All results indicate that the investigated CSSR works effectively to introduce a single notch-band characteristic for the UWB antenna, like CSR performances.

UWB tapered microstrip antenna with wideband notch using single split ring resonators shaped parasitic conductor

This contribution presents the design of a wideband-notched UWB tapered antenna using a single split ring resonator (SRR). The SRR is etched as parasitic loaded on the back side of the radiator element of the monopole antenna to achieve a frequency notch at 5.05-5.95 GHz. The dynamic resonance of the SRR element drives the notched center frequency and the coupling gap between the antenna ground plane and the SRR-shaped parasitic determines both the impedance bandwidth and the rejection level. The measurement results demonstrated that the proposed antenna can guarantee a wide bandwidth of about 1GHz with an unwanted wideband notch avoiding interferences caused by coexisting WLAN systems. As part of the optimization design, we analyzed the effect of the coupling gap between the SSR parasitic and the antenna ground plane.

Low pass filter design with wide rejection based on array of modified CSRRs configuration

This contribution presents the design of a low pass filter LPF with wide rejection based on modified complementary single split ring resonator (CSRR). The CSRRs are etched on the back side of the transmission and connected by slot line to achieve the desired resonance frequency. The quasi-static resonance of the CSRRs elements drives the cut-off frequency of the LPF and closed fundamental resonances achieve the wide rejection. Two Array configuration are proposed and demonstrate a good improvement in term impedance bandwidth of LPF rejected band. A good agreement match is shown between presented measured and simulated results. As part of the optimization design, we analyzed the behaviors of the initial filtering structure with two different CSRR radius.

Improvement of notch performances for UWB monopole antennas using CSRR and SSRR

In order to improve the notch performance for UWB monopole antennas, a synthesis design of single band-notched UWB antenna using the Single Split Ring Resonator SSRR and Complementary Split Ring Resonator CSRR, is presented. These techniques provide a wide rejection with enhancement of rejection level, due to the high coupling between the SSRR and the ground plane and the use of the CSRR dynamic resonance. Proposed monopole antennas with loaded SSRR and CSRR particle are fabricated and measured to validate the design performance. A good agreement is achieved between measurement and simulation.

Selectivity improvement in dual-band band pass filter by coupled complementary split ring resonators

With the advent of modern wireless communication technologies, single transceivers operating at multiple frequency bands have become popular. However, there are challenges in the design of dual-band filter supporting high performances and compact size. In this paper we propose the design of dual-band bandpass filter for Worldwide Interoperability for Microwave Access (WiMAX) and Wireless Local Area Network (WLAN) applications, providing selectivity enhancement using complementary split ring resonators CSRRs. It consists of two-pole parallel coupled bandpass filter with null coupling gap for middle section, as shown in Fig.1. From Fig.2, it can be observed that the filter exhibits good performance in term of return loss with low insertion loss in the desired frequency bands of 3.4 GHz and 5.5 GHz. However the rejection between bands is poor. This limitation can be overcomed by etching two CSRRs in the ground plane, exactly below the 50 Ω transmission line to improve the filter response. Fig.2 shows the cases implementing the CSRRs compared to the initial design. It can be seen that by using the same CSRR radius (2.2 mm) we achieve good rejection values at 4.2 GHz, whilst introducing slight band shifting and degradation in the WLAN band. However by applying two different radius (1.5 mm and 2.2 mm), a good response is obtained with insertion loss lower than the first case for the WiMAX band and sharp rejection at 6.7 GHz. The proposed design allows the potential implementation of simple and low cost dual band filters, scalable to different systems.

Stacked CPW-fed antenna for satellite applications with gain enhancement

This paper presents the design and implementation of a stacked CPW-fed antenna for satellite applications at Ku-, K-and Ka-bands for user terminals. The stacked structure combines two antennas. The base element consists of a CPW-fed patch antenna with modified CPW elements printed on Rogers TMM4 substrate. Above this base, a rectangular parasite patch was placed as a second layer using Arlon substrate with a high dielectric constant of 10.2. The two layers, base and parasitic patch, were separated by an air gap. This configuration reduces the antenna beam width and allows two-folding the antenna gain enhancement. The numerical simulations have been validated with experimental results.

Design of a tetra-band compact printed antenna for vehicular communications

This paper presents a simple and powerful design of a closely C-shaped microstrip patch antenna for wireless access in vehicular environment. Other wireless technologies such as WLAN, WiMAX, C-band, 5GHz U-NII, X-band and Ku-band applications are also supported. The microstrip patch antenna has been designed on the FR-4 substrate of 4.4 and thickness of h = 1.5mm, with a whole dimension of 25mm × 22mm. The proposed antenna can synchronously operate in multiple frequencies, covering four bands: [2.3538GHz-2.5388GHz], [5.0243GHz-8.0607GHz], [9.2403GHz-10.595GHz], [12.67GHz-15.182GHz]. To being small size, the new antenna exhibits stable far field radiation characteristics in the entire operating bandwidth with a relatively high gain, especially in the broadside direction which is suitable for vehicular systems. Using a full wave electromagnetic commercial simulator CST, a comprehensive study is detailed to understand the characteristics of the antenna in terms of electrical performances by considering reflection coefficient, radiation patterns, gain and VSWR. Results show, that the antenna is suitable for multiband wireless communication systems.