A dual-beam micro-CPW leaky-mode antenna

A quasi-planar leaky-mode antenna employing the second higher order leaky mode of even symmetry in its leaky-wave regime has been proposed for a new antenna configuration consisting of a microstrip and a coplanar waveguide (CPW) on both sides of the substrate. The new antenna, also known as the micro-CPW antenna, is directly fed by a CPW line without matching circuit. One particular K-band antenna of 36 mm long [about 2.7 free-space wavelengths (/spl lambda//sub 0/) at 22.1 GHz] shows 5.3% impedance bandwidth for VSWRs less than 2.0 for frequencies between 21.927-23.110 GHz, 11.0-dB antenna gain, and 90.02% efficiency. Detailed analyses show that the dual-beam antenna is linearly polarized along two slanted lines, which lie in the longer axes of the ellipses that approximate the radiation contours. Both theoretical and experimental data for the micro-CPW antenna agree very well for the particular design. The proposed micro-CPW antenna is suitable for active integrated antenna integration at higher microwave and millimeter-wave frequencies.