Jamal Zbitou

Hybrid rectenna and monolithic integrated zero-bias microwave rectifier

In this study, we have developed a hybrid sensitive rectenna (rectifier + antenna) system at 2.45 GHz. To achieve this system, we have first optimized and validated a zero-bias microwave sensitive rectifier using commercial Schottky diodes. We have then optimized and achieved a 2times2 patch antenna array, which is associated to the microwave rectifier in order to validate the rectenna system, where an RF-dc conversion efficiency of 56% has been observed experimentally. In order to minimize the rectenna dimensions, we have conducted a study using the OMMIC ED02AH 0.20-mum GaAs pseudomorphic high electron-mobility transistor process to develop and achieve a monolithic rectifier at 2.45 GHz with RF-dc conversion efficiency of 65%

Circular polarized square patch antenna array for wireless power transmission

Wireless power transmission is a process that takes place in any system where electrical energy is transmitted from a power source to an electrical load without a wired connection. Wireless transmission is ideal in cases where instantaneous or continuous energy transfer is needed, but interconnecting wires are inconvenient, hazardous, or impossible. Antenna has become the most vital element in any RF system due to its capability as a radio wave transceiver. A properly designed antenna is desirable to ensure efficient transfer of energy. This paper proposes a square patch antenna array 3×3 designed with a circular polarization using slots for wireless power transmission, through radio wave frequency of 2.45GHz. The array is being designed and simulated by using CST microwave software.

Ku-band waveguide band-pass filter with iris radius

This paper presents the design, simulation, and implementation of band pass filters in rectangular waveguides with radius, having 0.1 dB pass band ripple and 6.3% ripple at the center frequency of 14.2 GHz. A Mician microwave wizard software based on the Mode Matching Method (MMM) was used to simulate the structure of the filter. Simulation results are in good agreement with the measured one which improve the validity of the waveguide band pass filter design method.

ULTRA-BROADBAND HIGH EFFICIENCY MODE CON- VERTER

In this paper, we develop a small-sized mode converter with high performance, high conversion e-ciency and instantaneous bandwidth as high as 55%. This mode converter transforms energy from the TM01 flrst high-order mode towards the fundamental TE11 circular waveguide mode The proposed structure increases the free spurious operating bandwidth in comparison with the existing results in literature. An X/Ku-bands experiment prototype unit was designed, ensuring practical return losses better than 28dB and insertion losses less than 0.1dB (conversion e-ciency > 98:8%) within the entire frequency bandwidth ranging from 9.25GHz to 16.25GHz The presented architecture ofiers useful features such as very wide bandwidth, small size, easy achievement as well as excellent performance, which makes it very suitable for High-power microwave (HPM) sources that generate the TM01 circular waveguide mode. In these cases, the TE11 mode is needed since it has a convergent radiation pattern able to drive conventional antennas. Moreover, this compact concept is fully scalable to any millimeter frequency band.

Fractal multiband planar antenna for wireless power transmission

In this paper we have developed and designed a low cost fractal Multi band microstrip antenna structure. This antenna is validated in the ISM (Industrial Scientific and Medical) band at 2.45 GHz and 5.8 GHz. The aim of this work is to develop an antenna which can be associated with an RF-DC rectifier to design a rectenna system for wireless power transmission “WPT”. The technique used to have a multiband structure is the fractal geometry. The final circuit is a fractal multiband antenna with 65 × 30 mm2 as dimensions.

Miniaturization and reduction of mutual coupling for four arrays antennas using new structure of EBG

The design of more than one antenna system called antenna arrays. Patch antenna arrays are used extensively due to their high directivity and gain, also light weight and low cost. In antenna arrays energy is wasted in backward radiation as well as losses due to mutual coupling. Placing of elements close to each other can minimize the overall size of an array. On the other hand, a major drawback of this type of antenna arrays is mutual coupling; that depends on the separation between the elements, causes unfavorable effects on antenna characteristics. The use of Electromagnetic Band Gap structures, also called photonic band gap (PBG) structures in the antenna arrays can limit the coupling by suppressing the surface waves. In this paper, a novel electromagnetic band gap (EBG) surface has been introduced by some modifications in conventional mushroom-like EBG structure which has more compact electrical dimensions. This structure is proposed to be placed in between four patch arrays antennas to reduce the mutual coupling loss. The investigation included E coupling direction, and antennas array system is analyzed using CST mws. A significant value of −27.036 dB mutual coupling reduction is reached at 5.8 GHz resonant frequency.

Novel design of a miniature fractal microstrip CPW fed antenna for RFID reader

This work presents the miniaturization of a single rectangular microstrip antenna at 2.45 GHz in the ISM “Industrial Scientific and Medical” band by using the fractal technique. This microstrip antenna has A CPW fed and designed for RFID reader system on FR4 substrate with dielectric constant of 4.4, and simulated performing CST Microwave Studio. The total area of the final circuit is 21.22 × 32.05 mm2.The validated antenna has a good matching input impedance range from 2.304 GHz to 2.625 GHz with a stable radiation pattern, a loss return equal to -35.9 dB, and a gain of 2.2 dBi.

Novel design of a miniature L-slot microstrip CPW-fed antenna for RFID reader

This work presents the miniaturization of a single rectangular microstrip antenna at 2.45 GHz in the ISM “Industrial Scientific and Medical” band by using the slots technique. This microstrip antenna has a CPW fed and designed for RFID reader system on FR4 substrate with dielectric constant of 4.4, and simulated performing CST Microwave Studio. The total area of the final circuit is 19 × 31 mm2. The validated antenna has a good matching input impedance range from 2.338 GHz to 2.573 GHz with a stable radiation pattern, a loss return of -40 dB, and a gain of 1.78 dBi.

Compact dual-band microstrip slot antenna for UHF and microwave RFID applications

This paper presents a new dual-band microstrip slot antenna using two inverted L-shaped slots embedded on the radiating patch, suitable for Radio Frequency Identification (RFID) applications especially designed for RFID readers and it operates at 910 MHz and 2.45 GHz. This antenna is designed with a reasonable gain, low profile and low cost achievement. The simulation results carried out by ADS and CST Microwave Studio electromagnetic solvers, demonstrate that we have good performances in term of return loss, gain, radiation pattern and efficiency for the desired frequency bands. This antenna has a total area of 48×47 mm2 and mounted on an FR4 substrate with dielectric permittivity constant 4.4, thickness of 1.6 mm and loss tangent of 0.025. All simulation results of the resonant frequency, return loss, radiation patterns and fields distributions are presented.

A Novel Wideband Bandpass Filter Using Coupled Lines and T-Shaped Transmission Lines with Wide Stopband on Low-Cost Substrate

This paper presents the design, simulation, fabrication and measurement of a wideband bandpass filter with wide stopband performance operating at 3.5 GHz. The proposed filter consists of two parallel coupled lines (T-PCL) centred by T-inverted shape. The location of transmission zeros can be adjusted by varying the physical lengths of T-inverted shape to improve the filter selectivity. The wide bandwidth is achieved through enhanced coupling between the input and the parallel coupled lines. Due to the transmission zeros in the lower and upper stopbands, the filter exhibits good performance including an extremely wide stopband and sharp attenuations near the passband together with low insertion and good return losses in the passband. The filter performance is investigated numerically by using CST-MWS. Finally, the microstrip wideband BPF with minimum insertion losses 0.3 dB, centred at 3.5 GHz with a 3-dB fraction bandwidth of 70% and four transmission zeros is implemented and verified experimentally. In addition, good agreement between the simulated and measured results is achieved.