A novel MEMS microwave power coupler based on GaAs for Ku-band (12.4~18 GHz) is presented to improve the existing technology for measuring microwave power based on the termination devices

such as thermistors

thermocouples

and diodes

because the signals are not available after power detection by these devices. By the designed coupler

the microwave power is coupled with the Coplanar Waveguide(CPW) line

and most of the CPW signals can be transmitted to the next stage circuit for further processing. In order to reduce the reflection losses and to obtain broadband response of the power sensor

two kinds of optimal methods with a tuned structure and a compensating capacitor are proposed. Optimizations of the design with HFSS has demonstrated that the return loss (

S

11

) and insertion loss (

S

21

) at the central frequency of 15.2 GHz have reached -42.90 dB and -0.15 dB

respectively and the deviation of

S

11

and

S

21

compared with the central frequency have reached ±6.41 dB and ±0.04 dB in the Ku-band. These results show the microwave power coupler has advantages of high isolation

low loss and broadband characteristics.