This paper presents design and simulation of uniform structured RF MEMS capacitive shunt switch using FEM tool and HFSS software. The switches with different shaped meanders and perforations which result in less spring constant, less pull-in voltage, high isolation loss, high switching speed and low insertion loss have been designed. From the simulated results it is observed that the rectangular perforations gives the better results, when compared with square and cylindrical shaped perforations. Comparative study is done for zigzag, plus and three square shaped meander along with rectangular perforations on each structure. When the gap between the dielectric and the movable beam is 0.8 µm, the up state capacitance for HfO2 is 4.06fF and for Si3N4 is 3.80fF. The downstate capacitance for HfO2, Si3N4 is 49fF, 26.9fF respectively. The capacitance ratio is 120.6. Poly-tetra-fluoro-ethylene material is given for the movable beam whose young’s modulus is 0.4 GPa and the spring constant is calculated theoretically for each structure; by using this the pull in voltage and the settling time are calculated. Step switch with three square Meander has switching time 10.25 µs, pull in voltage as 2.45 V. By using HFSS 3-D electromagnetic model we observed the return loss (S11) is less than −60 dB, the insertion loss is less than −0.07 dB in the range of 1–40 GHz frequency and switch isolation (S21) is −61 dB at 28 GHz frequency.

Design and performance analysis of uniform meander structured RF MEMS capacitive shunt switch along with perforations

In this paper, we have designed, simulated, fabricated, and characterized a clamped-clamped micro mechanical structure-based shunt capacitive RF MEMS switch. The clamped–clamped micromechanical structure is micromachined using a gold metal thickness of 500 nm. AlN is used as a dielectric material, and it is deposited using the dc sputtering PVD process. In the MEMS technology, particularly in devices fabrication, releasing the membrane is a difficult task, and here, we have presented a novel wet process to release the membrane. Primarily, the S1813 sacrificial layer is etched by using the piranha solution and cleaned with the IPA solution. Critical point drying is done after fabrication to reduce the stiction effect on the switch. Overall, the switch requires the pull-in voltage of 5.5 V for 1.8- $\mu \text{m}$ displacement. In the process of optimization, primarily, the switch is designed and simulated using finite-element method tools. The reliability of the capacitive RF MEMS switches depends on the stiction problem caused by dielectric charging, and the proposed capacitive switch dielectric charging behavior is characterized using the CV curve method.

Fabrication and Characterization of Capacitive RF MEMS Perforated Switch

This paper is about, the design and analysis of shunt capacitive RF MEMS switch with less actuation voltage, low insertion losses and high isolation losses. The switch design is incorporated the El...

Design and analysis of CPW based shunt capacitive RF MEMS switch

This paper presents a comprehensive study on radio frequency-microelectromechanical systems (RF-MEMS) switches, which are expected to be extensively integrated into 5G infrastructures. The specifications of the RF-MEMS switch in use case and scenario for 5G have been summarized in part 2 and followed by the study of the state-of-the-art RF-MEMS switches in part 3. Both metal-contact and capacitive RF-MEMS switches, which have been developed and fabricated within the last two decades, are studied and tabled. In order to meet with the specification requirements of 5G scenario, the performance and characteristics of the RF-MEMS switches should be enhanced, such as acceptable RF performance, low actuation voltage, good reliability, short switching time, multiband topology, and on-chip integration and packaging. Different techniques for the improvement of the RF-MEMS switches' properties, for instance low spring constant, large actuation area, diverse actuation methods, push-pull mechanism, modified driving voltage waveform, inductive compensation, and so on, have been thoroughly investigated, classified, and summarized in part 4, which serves as the main contribution of the review. The findings from this review can be beneficial for further RF-MEMS switches' design and improvement. The upgraded RF-MEMS switches are capable of satisfying the growing need of cutting edge performance for 5G or high-performance applications.

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Comprehensive Study on RF-MEMS Switches Used for 5G Scenario

Due to their high isolation, low insertion loss, high linearity, and low power consumption, microelectromechanical systems (MEMS) switches have drawn much attention from researchers in recent years. In this paper, we introduce the research status of MEMS switches in different bands and several reliability issues, such as dielectric charging, contact failure, and temperature instability. In this paper, some of the following methods to improve the performance of MEMS switches in high frequency are summarized: (1) utilizing combinations of several switches in series; (2) covering a float metal layer on the dielectric layer; (3) using dielectric layer materials with high dielectric constants and conductor materials with low resistance; (4) developing MEMS switches using T-match and π-match; (5) designing MEMS switches based on bipolar complementary metal–oxide–semiconductor (BiCMOS) technology and reconfigurable MEMS’ surfaces; (6) employing thermal compensation structures, circularly symmetric structures, thermal buckle-beam actuators, molybdenum membrane, and thin-film packaging; (7) selecting Ultra-NanoCrystalline diamond or aluminum nitride dielectric materials and applying a bipolar driving voltage, stoppers, and a double-dielectric-layer structure; and (8) adopting gold alloying with carbon nanotubes (CNTs), hermetic and reliable packaging, and mN-level contact.

https://www.mdpi.com/2072-666X/9/4/185/pdf

Research and Analysis of MEMS Switches in Different Frequency Bands

This Paper reports on investigation of High Con Coff ratio Capacitive Shunt RF MEMS Switch and detailed comparison between uniform three meander beam with non-uniform single meander beam RF MEMS switch. RF MEMS Switches are designed for operation in the range 5---40 GHz. Pull in analysis is performed with gold as a beam material. Simulation reveals that use of high K dielectric material can drastically improve the capacitance ratio of switch. For the same geometry, pull in voltage is 2.45 V for HfO2, 2.7 V for Si3N4 and Capacitive Ratio of the switch with Si3N4 is 83.75 and Capacitive Ratio with HfO2 is 223 at 2g0 (air gap) and 0.8 μm thickness of beam. The Radio Frequency performance of RF MEMS switch is obtained by scattering parameters (insertion loss, Return loss and isolation) which are mainly dominated by down to up capacitance ratio and MEMS bridge geometries. RF analysis shows that insertion loss as low as ź0.4 dB at 20 GHz and isolation as high as 80 dB at 20 GHz can be achieved. Investigation of three uniform meander Design and non-uniform single meander design reveals that use of non-uniform design reduces the design complexity and saves substrate area still maintaining almost same device performance. S-parameter analysis is carried out to compare device performance for both structures. DC analysis of the proposed switch is carried out using Coventorware and RF analysis is performed in MATLAB.

Performance analysis of RF MEMS capacitive switch with non uniform meandering technique

This paper deals with the investigation of high Con Coff ratio capacitive shunt RF MEMS switch and reports a detailed comparison between uniform three meander beam with non-uniform single meander beam RF MEMS switch. RF MEMS Switches are designed for operation in the range 5 -40 GHz. Static Pull in analysis is performed with gold as a beam material. Simulation reveals that use of high K dielectric material can drastically improve the capacitance ratio of switch. For the same geometry, pull in voltage is 2.45 V for HfO2, 2.7 V for Si3N4 and Capacitive Ratio of the switch with Si3N4 is 83.75 and Capacitive Ratio with HfO2 is 223 at 2g0 (air gap) and 0.8 μm thickness of beam. The Radio Frequency performance of RF MEMS switch is obtained by scattering parameters analysis (insertion loss, return loss and isolation loss) which are mainly dominated by down to up capacitance ratio and MEMS bridge geometries. RF analysis shows that insertion loss as low as -0.4 dB at 20 GHz and isolation as high as -60 dB at 20 GHz can be achieved. Investigation of uniform three meander design and non-uniform single meander design reveals that use of non-uniform design reduces the design complexity and saves substrate area while maintaining almost same device performance. S-parameter analysis is carried out to compare device performance for both structures. DC analysis and beam deflection analysis of the proposed switch is carried out using FEM Coventorware and RF analysis is plotted in MATLAB.

Non uniform meander based low actuation voltage high capacitance ratio RF MEMS shunt capacitive switch

A double complementary split-ring resonators (CSRR) dumbbell-shaped defected ground structure (DB-DGS) bandstop filter is designed and proposed on FR-4 dielectric substrate with compact size 30.91×34.78 mm2 and low return loss in passband at 2.28 GHz frequency. The proposed CSRR DB-DGS bandstop filter is designed with insertion loss of −28.06 dB in stopband and −0.66 dB return loss. Also, it is compared with the single CSRR DB-DGS which has sharp roll-off factor. The proposed design is the modified version of the designs used with single CSRR. The proposed design is compared with the existing designs for the better outcomes of the BSF CSRR DB-DGS.

Design of Bandstop Filter using Double Dumbbell Shaped CSRR in Ground

The high gain, high speed/data rate, high capacity, and beamforming antennas are required for the present generation of mobile and wireless applications to satisfy the exponentially growing demands of the users. This paper presents low mutual coupling multiple input-multiple output (MIMO) array antenna for millimetre-wave (mmw) application. The MIMO-array beamforming antenna with 2:1 VSWR band is proposed for 28.0 GHz and covers 27.04–28.35 GHz frequency band, which is suitable for mm-wave n261 5G-band which cover the frequency range from 27.5–28.35 GHz. It consists of $$2\times 12$$ antenna array elements and the prototype is designed on low loss Rogers Duroid 5880 substrate of size $$51.45 \times 36.87\,{\text{mm}}^2.$$ The beamforming MIMO antenna covers $$\pm \,20^{0}$$ main lobe directions. The mutual coupling at the MIMO-array ports is less than 28.0 dB. The radiation efficiency and the gain in the presented band are more than 93.0% and more than 13.99 dBi. The ECC in the presented frequency band is $$\le 10^{-4}$$ , which is one of the advantages of the proposed design. The design covers indoor and outdoor Gaussian applications, and has 1.31 GHz TARC active bandwidth. It has 4.65% simulated and 4.73% measured fractional bandwidths. 

/pdf/beamforming-mimo-array-antenna-for-5g-millimeter-wave-22lwn65u.pdf

Beamforming MIMO Array Antenna for 5G-Millimeter-Wave Application

In this paper, antenna designed is proposed for Ultra wideband 2×2 MIMO antenna design with high isolation for THz application, it is designed using rectangular shape radiator with a cut of circular shape and occupies the size of 133×255 μm2which provide -10 dB impedance in 5.5 to greater than 10 THz frequency band as well as it is discussed the method to achieve better isolation, this design shows isolation parameter -66.27 dB (S12) and -69.6 dB (S21) at 8.19 THz. For the suitability of antenna for communication system CCL and TRAC is also calculated which are in acceptable limit.

Ajay Parmar

Papers

Performance analysis of RF MEMS capacitive switch with non uniform meandering technique

Non uniform meander based low actuation voltage high capacitance ratio RF MEMS shunt capacitive switch

Design of Bandstop Filter using Double Dumbbell Shaped CSRR in Ground

Beamforming MIMO Array Antenna for 5G-Millimeter-Wave Application

Ultra Wideband MIMO Antenna Design with High Isolation for THz Application