# Research and Analysis of MEMS Switches in Different Frequency Bands
## 3 The Research Status of MEMS Switches in Different Frequencies
### Research Regarding Insertion Loss and Isolation of MEMS Switches in Different Bands
#### 3.1.5 Other Types of MEMS Switches in Different Frequency Bands  
In addition to the above MEMS switches, many other types of switches were developed to achieve excellent insertion loss and isolation. Table 5 summarizes other types of MEMS switch performance parameters in different frequency bands. [PERSON] et al. [46] achieved low insertion loss and high isolation using a novel CPW configuration with discontinuities in a capacitive MEMS switch, in which a new capacitance and inductance were added in series with the equivalent circuit model. The MEMS ohmic switch designed by [47] realized low insertion loss and high isolation using a cantilever beam with multiple contacts and shunt contacts on the cantilever beam connected with the ground lines in the OFF state, which resulted in an improved isolation, and disconnected with the ground lines in the ON state, which resulted in an improved insertion loss. The MEMS metal-contact switch proposed by [PERSON] et al. [48] achieved high isolation using a see-saw system, which resulted a high isolation gap. The capacitive MEMS switch with parallel-support beam proposed by [PERSON] et al. [49] also obtained excellent insertion loss and isolation performances. A novel metal-contact MEMS switch with a bidirectional, electrothermal MEMS actuator designed by [PERSON] et al. [50] achieved low insertion loss of 0.25 dB at 35 GHz and high isolation of 32.5 dB at 35 GHz and also realized low pull-down voltage of 0.3-0.5 V due to the high thermal conductivity and high thermal expansion coefficient of the actuator. [PERSON] et al. [51] achieved a low insertion loss of 0.3 dB at 35 GHz using a \(\lambda\)g/4 sector open stub in a capacitive MEMS switch. [PERSON] et al. [52] designed a dimple formed along the signal line on top of a bridge to create good contact and achieve good \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Number** & **Insertion Loss** & **Isolation** & **Actual Voltage** & **Reference** \\ \hline \multirow{4}{*}{centimeter} & 0.25 dB@20 GHz & 58 dB@21 GHz & - & [46] \\  & 0.1 dB@20 GHz & 22.3 dB@20 GHz & - & [47] \\  & 0.5 dB@10 GHz & 28 dB@10 GHz & 15 & [48] \\  & 0.25 dB@20 GHz & 40 dB@30 GHz & 6.2 V & [49] \\ \multirow{4}{*}{Q} & 0.25 dB@35 GHz & 32.5 dB@35 GHz & 0.3–0.5 V & [50] \\  & 0.3 dB@35 GHz & 20 dB@35 GHz & 15.8 V & [51] \\  & \(<\)1 dB & \(>\)22 dB & 15.2 V & [52] \\ \multirow{4}{*}{V} & 1.12 dB@50 GHz & 42.2 dB@50 GHz & 15 V & [53] \\  & 0.4 dB@60 GHz & 35 dB@60 GHz & 40–44 V & [54] \\  & \(<\)0.2 dB & \(>\)22 dB & - & [55] \\ \multirow{4}{*}{W} & \(<\)6 dB & 20–22 dB(Si) & 15.2 V & [52] \\  & 15–30 dB(GaAs) & & & \\ \cline{1-1}  & 0.36 dB@77 GHz & 17.3 dB@77 GHz & 39 V & [56] \\ \cline{1-1}  & 2.23 dB@80 GHz & 41.4 dB@800 GHz & 15 V & [53] \\ \cline{1-1}  & \(<\)1 dB & 10–50 dB & 40 V & [57] \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Other types of MEMS switch performance parameters in the centimeter band. isolation in the V and W bands. [PERSON] et al. [PERSON] et al. (2018) achieved high isolation and low insertion loss in the V and W bands using two-directional motions, and the data is listed above. Both waveguide switches were designed in [PERSON] et al. (2018); [PERSON] et al. (2018). A single pole, single throw (SPST) waveguide switch designed by [PERSON] et al. [PERSON] et al. (2018) exhibited a low insertion loss of 0.6 dB at 60 GHz and high isolation of 32 dB at 60 GHz utilizing a reconfigurable MEMS surface. A novel, monolithic MEMS waveguide switch proposed by [PERSON] et al. [PERSON] et al. (2018) achieved an insertion loss of less than 0.2 dB and an isolation of more than 22 dB at 60-75 GHz by embedding the MEMS multilayer cantilever beams made of silicon/chrome/gold in the waveguide channel, and the beam shape was tapered. Both the signal line with contact bumps and the tip of the cantilever beam were designed as a fork tip, which minimized their overlapping area, in the paper written by [PERSON] et al. [PERSON] et al. (2018), and their MEMS switch realized low insertion loss of 0.36 dB at 77 GHz.