UWB coplanar waveguide‐fed coplanar strips rectangular spiral antenna

This article proposes an ultra‐wideband coplanar strips (CPS) rectangular spiral antenna that is fed by coplanar waveguide (CPW). The CPS is formed by gradually reducing the width of the CPW ground planes without the need of a balun. The antenna operates in the frequency band (3.5‐10.6 GHz) and has miniaturized size of 50 × 40 × 0.508 mm on a Rogers RO4003C substrate. The CPS spiral is terminated with a 100 Ω chip resistor for matching. A parametric study was performed to choose the CPS spiral dimensions. A good agreement is found between simulations and measurements in the radiation pattern and the return loss which was found to be better than 10 dB over the band. The measured peak gain ranges between 1 and 4.7 dBi.     

Ultra-wideband back-to-back CBCPW-to- CBCPW transition

A new ultra-wideband back-to-back conductor-backed coplanar waveguide (CBCPW)-to-CBCPW transition structure is presented and implemented. The design of this transition is based on vertical resonant coupling via a rectangular slot between two stacked CBCPW lines. According to careful design and optimisation, the CBCPW-to-CBCPW transition results show a good performance in terms of bandwidth, which is about 12 GHz     

An efficient hexagonal switched beam antenna structure based on Fabry-Perot cavity leaky-wave antenna

A novel design of switched beam antenna (SBA) system based on Fabry-Perot cavity leaky-wave antenna (FPC LWA) is designed and fabricated for base station operating in the unlicensed ISM central frequency band at 5.8 GHz of the wireless local area network (WLAN) standard. The proposed SBA is designed with hexagonal shape of FPC LWA Arrays in order to get 360° of coverage. The single element of FPC LWA array is composed of a patch antenna and covered by a Partially Reflective Surface (PRS), which is composed of a Metal Strip Grating and printed on a high permittivity Superstrate. First, the Transmission Line Model of FPC LWA is introduced to analyse and calculate the far-field components in E- and H planes by using the Transverse Equivalent Network. This approach is then compared with other full wave’s commercial software such as Ansoft HFSS and CST Microwave Studio. Second, a parametric study is performed to evaluate the effect of the angle formed by the two successive FPC LWA on the radiation efficiency of the activate sector. To examine the performance of the proposed SBA, experimental prototype was fabricated and measured. As a result, multiple orthogonal beams (six beams) of 10 dBi of gain with low Side Lobes Level and 360° of coverage are produced. This SBA structure is suitable for WLAN communication systems.     

Experimental investigation of a new butler matrix using slotline technology for beamforming antenna arrays

The design and realisation of a 4 times 4 Butler matrix for multibeam antenna arrays operating at 5.8timesGHz are described. The matrix is implemented on a single layer slotline structure to avoid using air bridges as required in coplanar waveguide technology. In this design, a new hybrid coupler and a crossover using slotline technology were designed and fabricated, and they are used to build a new Butler matrix. To examine the performances of the proposed matrix, numerical simulations and experimental measurements were carried out; the comparison between simulated and experimental results shows a good agreement.     

Wideband slot antenna using a new feeding technique for wireless applications

This article presents a new wideband slot antenna for wireless applications at 5.8 GHz. To improve the antenna bandwidth, a new feeding mechanism based on a capacitively‐ and inductively‐coupled slot is proposed. To demonstrate this approach, an experimental antenna prototype operating at the 5.8‐GHz band was designed, fabricated, and measured. The obtained results indicate very good agreement between the numerical and experimental results. The proposed antenna achieves a 28.5% bandwidth, a 5.7‐dBi gain, and a ?15‐dB front‐to‐back ratio, which are very sufficient for broadband wireless applications. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.     

Ultra-wideband bandpass filter using back-to-back CBCPW-to-CBCPW transition

A new ultra-wideband bandpass filter using a back-to-back CBCPW-to-CBCPW transition structure is presented. The filter is composed of two CBCPW-to-CBCPW transitions and a section of a CBCPW line section used as a multiple-mode resonator. Using this transition, a new ultra-wideband filter prototype was designed, fabricated and measured. Obtained results show that the proposed filter can easily cover the band from 3.1 to 10.6 GHz.     

Ultra-wideband microstrip to CB-CPW transition applied to broadband filter

A new ultra-wideband microstrip to conductor backed coplanar waveguide (CB-CPW) transition structure is presented and implemented. Results show good performance in terms of bandwidth, which is about 12 GHz. Using this transition, a new ultra-wideband filter was designed and fabricated. Simulated and measured results show that the filter can cover the band from 3.1 to 10.6 GHz (-10 dB bandwidth)     

Ultra‐compact 4‐port DR antenna for multi‐input multi‐output standards

Here, an ultra‐compact Multi‐Input‐Multi‐Output (MIMO) antenna system is presented for Wireless Local Area Network (WLAN) applications. The proposed antenna compactness approach is based on using Cylindrical‐Dielectric‐Resonator‐Antenna (CDRA) symmetry with the help of image theory to achieve the best size reduction of the resonators and maintain the resonance frequency of the original CDRA. The electric/magnetic walls approach is utilized to miniaturize the size by exploring the symmetry and antisymmetry of the resonant mode. First, a CDRA for MIMO system is designed and tested in terms of return loss and radiation efficiency. Then, two configurations of MIMO‐Antennas (two and four ports) are examined by using the same substrate size. The 2‐port‐MIMO antenna is built from two half‐CDRs (HCDRs) facing each other. Similarly, four‐quarter‐CDRs (QCDRs) are created to form a 4‐port MIMO antenna system. As a result, a 75% size reduction is achieved (size of 30 × 30 × 7.62 mm³). The measured impedance bandwidth for the 4‐port MIMO antenna is 5.4% (5.4‐5.7 GHz), with more than 15 dB isolation levels. Proper levels of Envelope Correlation Coefficients (ECCs) are also achieved (1 × 10^?2‐4 × 10^?2), with a channel capacity loss (CCL) of 0.04 bits/S/Hz. The proposed MIMO antennas are suitable for compact wireless communication systems.     

CPW multilayer slot-coupled directional coupler

A new 3 dB CPW multilayer slot-coupled directional coupler between two CPW lines coupled through a rectangular slot etched on a common ground plane located between these lines is presented. The proposed directional coupler showed promising results, especially in terms of bandwidth (/spl sim/80%). The simulated results are compared with the measured data, and good agreement is reported.