This paper describes a novel, low-profile antenna for the satellite digital audio radio service. The antenna consists of a thin cavity with a pair of crossed slots having unequal length. Both slots are fed by a single-probe-type feed, resulting in a simple low-cost structure. This antenna is left-hand circularly polarized toward the sky for satellite reception, and vertically polarizated toward the horizon for terrestrial reception. The result is a lowprofile antenna that can receive simultaneously from both satellite broadcasters and terrestrial repeaters, and can be built using low-cost printed circuit fabrication methods.

In this study, we investigate the fabrication of a micromachined microwave switch using the commercial 0.35 µm double polysilicon four metal (DPFM) complementary metal oxide semiconductor (CMOS) process and the post-process of only one maskless wet etching. The post-process has merits of easy execution and low cost. The post-process uses an etchant (silox vapox III) to etch the silicon dioxide layer to release the suspended structures of the microwave switch. The microwave switch is a capacitive type that is actuated by an electrostatic force. The components of the microwave switch are coplanar waveguide (CPW) transmission lines, a suspended membrane and supported springs. Experimental results show that the driving voltage of the switch is about 17 V. The switch has an insertion loss of -2.5 dB at 50 GHz and an isolation of -15 dB at 50 GHz.

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