Design, Implementation and Measurement of 26.6 GHz Patch Antenna using MEMS Technology M. Abdel-Aziz, H. Ghali, H. Ragaie, H. Haddara* E. Larique**, B. Guillon** and P. Pons*** Electronics and Comm. Eng. Dept., Ain Shams Univ., Cairo - EGYPT *MEMScAP – EGYPT, ** MEMScAP - FRANCE *** LAAS/CNRS - FRANCE Abstract This paper presents a 26.6 GHz patch antenna using MEMS technology. In this technology, the patch is suspended over a thin dielectric layer (membrane), which is deposited on a high index silicon substrate. In addition, the silicon substrate is fully etched under the patch, creating an air cavity region of very low dielectric constant (ε r ≅1). The antenna is directly fed using a microstrip line, and a CPW-microstrip transition is used for probe measurements of the antenna return loss. The design is performed using the 3D electromagnetic simulator HFSS ® . The measured antenna return loss is -17dB at 26.6 GHz, and the bandwidth is 4.5%. The antenna has a radiation efficiency of 61.7% and directivity of 7.9dB. The measured antenna cross-polarization level is less than -20 dB in both the E- and H-planes. I. Introduction Microstrip antenna is a very common element in telecommunications and radar applications since it provides a wide variety of designs, either planar or conformal. In addition, microstrip antennas could be fed by various techniques, besides its advantage of being compact and suitable for antenna array designs [1]. Recently, System-on-Chip (SOC) concept has become more in focus, implying that all passive and active components being integrated over silicon. The major problem in integrating antenna over silicon is the high dielectric constant (ε r =11.9). This has the drawbacks of easily excited surface waves, lower bandwidth, and degraded radiation efficiency. Another issue is the losses caused by the silicon conductivity. The first problem can be remedied by the use of a MEMS technology to remove the silicon substrate below the antenna, and consequently synthesize a locally low dielectric constant (ε r =1) region around the antenna [1]. The second problem is overcome by using a High Resistivity Silicon (HRS) substrate, where the losses due to the substrate conductivity are minimized, improving the antenna radiation efficiency. The idea of creating an air cavity underneath the antenna can take many forms. First, it is possible to synthesize a predetermined dielectric constant from 1 to 11.9 by partially etching the silicon underneath the patch antenna. This technique has been adopted in [1-3]. It is also possible to suspend the antenna over closely spaced holes in the substrate [4]. Another approach is to etch all silicon substrate and suspend the patch over a dielectric membrane, as in [5]. In the present case, a HRS substrate is used, which has been etched on the backside. The design procedure will be explained in the following sections, together with simulated and measured results. * On Leave from Ain Shams University