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RF MEMS shunt switch on CPW line: a typical switch schematic; b isolation; and c return loss (color figure online)
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This paper presents improved W-band (75–110 GHz) radio frequency characteristics of micro-electromechanical switches in T and π-matched configurations. The switch structures consist of Au metallic bridge (s) suspended over the coplanar waveguide (CPW) signal line drawn on quartz substrate. Here, a high impedance transmission line is introduced on b...
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Analysis and design of a novel high on/off capacitance ratio and low actuation voltage radio frequency microelectro-mechanical systems (RF MEMS) switch. Circuit topology and electrode topology of RF MEMS switches are analyzed. In order to decrease actuation voltage, the switch, using coplanar waveguide transmission line for signal transmission, are...
Citations
... Quartz (SiO 2 ) is the most abundant mineral in the crust of the earth and has numerous industrial and technical applications [35]. Quartz is inexpensive, it has excellent mechanical properties, and it is chemically stable [36,37]. Moreover, natural quartz has characteristic piezoelectric properties that strongly enhance the photocatalytic properties of ZnO [38,39]. ...
A natural piezoelectric quartz core was coated with environmentally friendly ZnO nanoparticles (GZn/PQz) for enhanced decontamination of ibuprofen (IBF) by adsorption and advanced oxidation. The adsorption properties were described based on the monolayer model of one energy site. The steric studies demonstrated a decline in active site density (Nm) and the saturation adsorption capacities (Qsat) with increasing temperature, and the best values were achieved at 25 °C (Nm = 38.42 mg/g and Qsat =145.6 mg/g). The number of adsorbed IBF molecules (n) (> 3 and < 4) suggested the uptake of 3 or 4 IBF molecules per receptor site in a vertical orientation and by a multimolecular mechanism. The adsorption energy values (-7.93 to -9.5 kJ/mol) suggest physical uptake processes. The thermodynamic functions reflected the exothermic and spontaneous properties of the reactions. GZn/PQz achieved IBF (50 mg/L) oxidation percentages of 100%, 93.8%, and 100% after 80 min (photocatalyst), 360 min (piezoelectric catalyst), and 40 min (piezo-photocatalyst), respectively. Hydroxyl radicals and superoxide radicals are essential oxidizing species during the oxidation of IBF by GZn/PQz. Based on the detected intermediate compounds, the oxidation pathway of IBF by GZn/PQz involved hydroxylation, decarboxylation/demethylation, and ring-opening processes.
... The devices such as pressure sensors, accelerometers, gyroscope, and temperature sensors are the few most sort after MEMS sensors for these applications [8,[11][12][13][14][15]. On the other hand, smart actuation mechanisms such as shape-memory effect, electrostatic, magnetic and piezoelectric are intelligently employed to perform the various desired microscopic operation with great precision [7,14,[16][17][18][19][20] Ever since the introduction of the famous mechanical resonator gate transistor reported by Nathan et al. [21], micro-resonators are the important building block of many MEMS devices [22][23][24][25][26][27][28][29]. Today, MEMS-based resonators have been used in oscillators [5], filters [16], gyroscope [11], micro-speaker [30], etc. ...
Aluminium nitride-based MEMS resonators are one of the interesting recent research topics for its tremendous potential in a wide variety of applications. This paper focuses on the detrimental effect of residual stress on the AlN-based MEMS resonator design for acoustic applications. The residual stress in the sputtered c-axis (< 001 >) preferred oriented AlN layers on Si (111) substrates are studied as a function of layer thickness. The films exhibited compressive residual stresses at different thickness values: − 1050 MPa (700 nm), − 500 MPa (900 nm), and − 230 MPa (1200 nm) with ± 25 MPa accuracy. A mushroom-shaped AlN-based piezoelectric MEMS resonator structure has been designed for the different AlN layer thicknesses. The effect of the residual stresses on the mode shapes, resonant frequencies, and quality factor (Q) of the resonator structures are studied. The resonant frequency of the structures are altered from 235 kHz, 280 kHz, and 344 kHz to 65 kHz, 75 kHz and 371 kHz due to the residual stress of − 1050 MPa (thickness: 700 nm), − 500 MPa (thickness: 900 nm) and − 230 MPa (thickness: 1200 nm), respectively. At no residual stress, the quality factors of the resonator structures are 248, 227, 241 corresponding to the 700 nm, 900 nm, and 1200-nm-thick AlN layers, respectively. The presence of the residual stress reduced the Q values from 248 (thickness: 700 nm), 227 (thickness: 900 nm), 241 (thickness: 1200 nm) to 28, 53, and 261, respectively.
... The devices like pressure sensors, accelerometers, gyroscope, and temperature sensors are the few most sort after MEMS sensors for these applications [8,[11][12][13][14][15]. On the other hand, smart actuation mechanisms like shape-memory effect, electrostatic, magnetic and piezoelectric are intelligently employed to perform the various desired microscopic operation with great precision [7,14,[16][17][18][19][20] Ever since the introduction of the famous mechanical resonator gate transistor reported by Nathan et al. [21], micro-resonators are the important building block of many MEMS devices [22][23][24][25][26][27][28][29]. Today, MEMS-based resonators have been used in oscillators [5], filters [16], gyroscope [11], micro-speaker [30], etc. ...
Aluminum nitride-based MEMS resonators are one of the interesting recent research topics for its tremendous potential in a wide variety of applications. This paper focuses on the detrimental effect of residual stress on the AlN based MEMS resonator design for acoustic applications. The residual stress in the sputtered c axis (<001>) preferred oriented AlN layers on Si (111) substrates are studied as a function of layer thickness. The films exhibited compressive residual stresses at different thickness values: -1050 MPa (700 nm), -500 MPa (900 nm), and -230 MPa (1200 nm). A mushroom-shaped AlN based piezoelectric MEMS resonator structure has been designed for the different AlN layer thicknesses. The effect of the residual stresses on the mode shapes, resonant frequencies, and quality factor (Q) of the resonator structures are studied. The resonant frequency of the structures are altered from 235 kHz, 280 kHz, and 344 kHz to 65 kHz, 75 kHz and 371 kHz due to the residual stress of -1050 MPa (thickness: 700 nm), -500 MPa (thickness: 900 nm) and -230 MPa (thickness: 1200 nm) respectively. At no residual stress, the quality factors of the resonator structures are 248, 227, 241 corresponding to the 700 nm, 900 nm, and 1200 nm thick AlN layers respectively. The presence of the residual stress reduced the Q values from 248 (thickness: 700 nm), 227 (thickness: 900 nm), 241 (thickness: 1200 nm) to 28, 53, and 261 respectively.
The miniaturization and low power consumption characteristics of RF MEMS (Radio Frequency Microelectromechanical System) switches provide new possibilities for the development of microsatellites and nanosatellites, which will play an increasingly important role in future space missions. This paper provides a comprehensive review of RF MEMS switches in satellite communication, detailing their working mechanisms, performance optimization strategies, and applications in reconfigurable antennas. It explores various driving mechanisms (electrostatic, piezoelectric, electromagnetic, thermoelectric) and contact mechanisms (capacitive, ohmic), highlighting their advantages, challenges, and advancements. The paper emphasizes strategies to enhance switch reliability and RF performance, including minimizing the impact of shocks, reducing driving voltage, improving contacts, and appropriate packaging. Finally, it discusses the enormous potential of RF MEMS switches in future satellite communications, addressing their technical advantages, challenges, and the necessity for further research to optimize design and manufacturing for broader applications and increased efficiency in space missions. The research findings of this review can serve as a reference for further design and improvement of RF MEMS switches, which are expected to play a more important role in future aerospace communication systems.
