Two-port 3D printed trefoil torus knot antenna with pattern diversity

A two-port trefoil torus knot antenna with pattern diversity is proposed. The antenna can generate both broadside pattern, and conical beam pattern. Broadside pattern is obtained by exciting a trefoil knot and a conical beam pattern is achieved by exciting a monopole. Both modes are engineered to operate in an overlapped frequency range. The prototype of the antenna structure operating at 2.45 GHz is realized using 3D printing and the performance is measured in an anechoic chamber. The measured overlapping impedance bandwidth (-10 dB) of both patterns is 16.49% from 2.28 GHz to 2.69 GHz with an isolation of 12 dB between two ports. Measured gain at 2.45 GHz is 8.37 dBi and 4.5 dBi for broadside pattern and conical beam pattern respectively. The proposed antenna can be used as pattern diversity ceiling mounted antenna for indoor communications.