# Comprehensive Review of RF MEMS Switches in Satellite Communications
## 4 Application in Reconfigurable Antennas  
The miniaturization of satellite communication systems can be achieved by using reconfigurable antennas to reduce the number of antennas in a device. Today, multimode and multi-band RF front-end transceivers are receiving great attention [159]. This is because they can support multiple communication standards, which helps in reducing power consumption, lowering costs, and minimizing signal loss. Figure 12 shows an example of a front-end transceiver that supports GSM/WCDMA/GPS. From the figure, it is evident that the switching network follows immediately after the antenna to enable sharing of the antenna across different frequency bands. The antenna switching network, composed of antenna switches, plays a key role in the overall performance of the multimode modulated front end. Figure 11: A 3D schematic view of serial-shunt switches: (**a**) [PERSON] et al. [157]. A, B, and C represent different pads, and the state of the switch is controlled by adjusting their voltages. Reprinted/adapted with permission from [157], 2022, IEEE. (**b**) [PERSON] [158]. Reproduced with permission from Springer Nature. (**c**) [PERSON] et al. [42]. Reprinted/adapted with permission from [42]. Copyright 2014, with permission from Elsevier. The development of the Internet of Things brings new requirements for antennas in wireless communication systems, especially in areas such as smart cities, smart transportation, and smart healthcare [160; 161]. These applications require antennas to be reconfigurable in frequency, polarization, and radiation direction. RAs (reconfigurable antennas) change their effective aperture of the radiation field by rearranging antenna currents or reconfiguring radiating edges, thereby altering the antenna's characteristics [162; 163; 164; 165; 166]. The characteristics of such antennas can be altered by changing the operating frequency, radiation pattern, or polarization behavior. Compared to traditional multi-antenna systems, reconfigurable antennas can significantly reduce hardware complexity and costs while maximally improving antenna performance, all while meeting the ever-changing operational requirements. Therefore, reconfigurable antennas are receiving great attention in fields such as satellite communication [164; 165; 167; 168]. A reconfigurable antenna can change its operating frequency, radiation pattern, and directivity according to different application needs, thus offering greater flexibility and efficiency. RF MEMS switches are widely used in satellite reconfigurable antennas, enabling reconfigurable multi-band antenna devices based on RF MEMS switches to be reconfigured step by step in microseconds to adapt to a variety of applications in different frequency ranges. Compared to traditional antennas, antennas integrated with RF MEMS switches can reduce parasitic effects and power loss [169]. For example, in phased array antennas, RF MEMS switches can be used to adjust the phase of signals, thus controlling the direction of the beam. This allows satellites to perform more precise beamforming and directional transmission, enhancing communication quality and coverage. [PERSON] and [PERSON] [170] described various design parameters to improve the performance of RF MEMS switches, which ultimately enhances the performance of beam-scanning and reconfigurable antennas. It is evident that the performance of antennas largely depends on the design and functionality of RF MEMS switches [171]. The application of these switches not only  
Figure 12: An example of a transceiver that supports different frequency bands [159]. Reprinted/adapted with permission from Ref [159], 2022, John Wiley and Sons. enhances the flexibility and efficiency of antennas but also helps meet the growing wireless communication needs of IoT. The advancement in antenna technology is becoming crucial, especially in ensuring fixed frequency and avoiding RF blockage [172] or interference from multiple RF sources [173].