Low Cost Bowtie Apertures for 18–40 GHz Spectrum Sensing and Monitoring

Two bowtie aperture antennas for 18–40 GHz spectrum sensing and monitoring are presented in this paper. The antennas are based on low cost printed circuit board, and coplanar waveguide (CPW) is used to feed the bowtie apertures. The antenna with nearly omni-directional radiation patterns has very small dimensions of 11 mm × 6.4 mm × 0.8 mm. For conformal installation on platforms or building walls, a plane reflector is added to the bowtie aperture, and an array of periodic patches is adopted as a superstrate for improving the radiation pattern and impedance matching. This unidirectional version has small dimensions of 12 mm × 8 mm × 2.8 mm. The proposed lost cost antennas are useful for spectrum monitoring applications as they are small in size, broadband, efficient, and flexible for installation.