Bassem Jmai

A Novel Reconfigurable MMIC Antenna with RF-MEMS Resonator for Radar Application at K and Ka Bands

This paper presents a new reconfigurable antenna based on coplanar waveguide (CPW). The design for reconfigurable antenna is based on monolithic microwave integrate circuit (MMIC). This scheme combines a CPW antenna and switchable resonator radio frequency micro-electro-mechanical system (RF-MEMS). The resonator RF-MEMS presents a meander inductor structure and tuning capacitor controlled by the applied DC voltage. This component can be used for the System on the Chip (SoC). Moreover, this device presents a compactness characteristic and the possibility to operate at high frequencies. The switch element allows changing the frequency band and the resonant frequency easily. The simulation results are shown between 10 and 40 GHz. The presented reconfigurable antenna can cover five bands: (26, 26.6) GHz, (26.4, 27.3) GHz, (27.3, 28) GHz, (29, 30.1) GHz and (30.13, 30.7) GHz. All simulation results were made by the High Frequency Structural Simulator (HFSS) software and validated by Computer Simulation Technology Microwave Studio (CST MWS).

Novel Conception of a Tunable RF MEMS Resonator

This paper presents a new monolithic microwave integrated circuit (MMIC) based on coplanar waveguide (CPW) design for a tunable resonator based on RF MEMS. This RF structure, which can be used for system on chip (SOC), is constituted with MEMS Bridge placed between two meander inductors and the tenability is controlled by a variable applied DC voltage. Moreover, this device presents a compactness characteristic and the possibility to operate at high frequencies. The resonant frequency and the bandwidth can be changed easily by changing the bridge gap of the RF MEMS. The numerical simulations of this novel structure of a tunable RF MEMS resonator were performed with the electromagnetic solvers CST MWS (Computer simulation Technology Microwave Studio) and validated by the more accurate electromagnetic solver HFSS (High Frequency Structural Simulator). The simulation results, for three different spacing of the bridge gap, show that the tunable frequency band are between 10 and 40 GHz with the two electromagnetic solvers and exhibiting three resonant frequencies (21, 23.1 and 24.6 GHz).The simulation results of the return loss using CST achieves 29 dB with an insertion loss less than 1 dB; However, the HFSS simulation shows similar performance in the resonant frequencies and in the bandwidth giving better results in terms of the return loss (about 35dB instead of 29 dB) and showing a good adaptation.

Miniaturisation of a 2-Bits Reflection Phase Shifter for Phased Array Antenna based on Experimental Realisation

In this paper, a controllable reflection type Phase Shifter (PS) is designed, simulated and implemented. The structure of the 2-bits PS consists of branch line coupler, delay lines and six GaAs FET switches controlled in pair. The phase shifting is achieved by turning ON one pair of switches. The circuit design is fabricated using FR4 substrate with dielectric constant equal to 4.7. The size of the realised circuit is 7cm×2.8cm. To reduce this size, two methods are used. First, shortened quarter-wave length transmission line in T model is employed to develop a compact branch-line coupler. Second, a loaded line with capacitor is used to reduce the dimension of delays lines. The two methods are combined to realise a PS with compact size equal to 4.5cm×1.96cm.

Controllable bridge of the RF-MEMS: Static analysis

This paper presents the design and the mechanical testing of the RF MEMS capacitive beam based on coplanar waveguide (CPW) design. The propose of this simulation is to make a comparative study on three different models (uniform bridge, Fixed-fixed flexure bridge and meander bridge) structures with four different materials (Nickel, Copper, Aluminum, and Gold). The simulation is obtained using comsol software. The proposed switch is considered as a moving membranes controlled by an applied DC voltage. The obtained results show that the Gold and Aluminum has the best displacement versus the applied voltage. The applied voltage of the model three based on meander modification becomes the third of the necessary voltage for the first model based on the uniform structure: [for example of the aluminum material: the pull in voltage equal to 47 V in model 1 and 15 V in model 3]. It is also observed that the low applied voltage corresponds Aluminium and Gold materials.

A dual band PIFA antenna for GSM and GPS applications

In this work, a dual-band PIFA (Planar Inverted F Antenna) is proposed for wireless applications. The antenna is conceived as a PIFA to have dual-band and good efficiency. The proposed antenna is only 58 mm × 33 mm. It is built on a huge 90 mm × 62 mm ground plane with a FR7 substrate thickness of 1.57 mm. The proposed antenna includes the GPS (Global Navigation Satellite System) bands, GSM. Simulation results are analyzed using CST software. The proposed antenna structure, performance loss, dual band frequencies, bandwidth and simulated current distribution are presented and discussed after parametric study.

Conception and simulation of above-IC CPW antenna

The antenna chips becomes very important component in microwave applications and for the wireless communication industry. In this work, different Coplanar Waveguide (CPW) antenna above-IC (integrate circuit) are analyzed and simulated by high frequency structural simulator (HFSS) based on finite element method (FEM). A comparative study has been done on their performances of different types of CPW antenna with some geometrical dimension. Furthermore, the return loss and radiation pattern were investigate in terms of gain radiation and directivity. The simulation results show that it is possible to have multiband CPW antenna by changing the geometry of the radio frequency (RF) patch in the shape of inverse U with a split-ring resonator.

EMC immunity test for capacitive shunt RF-MEMS switch

The Radio Frequency Micro-electromechanical system (RF MEMS) has compact geometries and are very used in Monolithic Microwave Integrate Circuit (MMIC) for different important applications with respect to their size and their effectiveness. Its effectiveness can be improved by reducing the Electro Magnetic Interference EMI problem with better Electromagnetic compatibility EMC immunity of the component. This work presents the EMC immunity testing of RF-MEMS for different substrate cases Silicon (Si), Gallium Arsenide (GaAs) and Silicon Carbide (SiC). This MEMS structure is exited by used the electromagnetic solver HFSS (high frequency structural an external parasite line which will induce an EM radiation around the MEMS component; In order to analyze the EM test immunity of the MEMS we simulator) based on finite element method for simulation. For the different substrates, a comparative study of the electric and magnetic fields is exposed and discussed. We have investigated also on the surface current densities on the RF line. The results show that the material SiC has better performances in the immunity test than Si and GaAs substrates.