Coplanar-to-Rectangular Waveguide Transitions Using Slot Antennas

A coplanar-to-rectangular waveguide transition using a dipole slot antenna is proposed in this paper. The advantage of this transition is that no intermediate transition and vias are needed in this direct transition. Parameter studies of this transition demonstrate that a transition having a fractional bandwidth of 22.85%, for which the return loss is larger than 15 dB, is achieved in the X-band (8.2-12.4 GHz). Furthermore, in order to enhance the bandwidth, the dipole slot antenna is replaced by a bowtie slot antenna. This design demonstrates a wider fractional bandwidth of 26.67%. Back-to-back transitions for both designs were fabricated and measured in order to verify these designs, and the measurement results agree well with the simulation results.