Broadband probe for efficient near field measurements

In this paper, we designed and fabricated the broadband probe with double ridged waveguide for broadband near-field measurements. An exponential taper ridge in the rectangular waveguide and novel waveguide transition were implemented for wideband impedance matching and compression of the higher modes. It has wideband characteristics and its measured impedance bandwidth ratio is approximately 123%(4.17:1) from 12.0 GHz to 50 GHz for SWR<3.0. And the peak radiation gain is 5.7~14.3 dBi. The performance of this probe is verified by the measured results and is in good agreement with the simulated results. It is possible that our designed broadband probe is applied to broadband near-field measurement under 50 GHz.