The Design of Broadband Probe for Efficient Near Field Measurements

In this letter, we designed and fabricated a broadband probe with a double-ridged waveguide for broadband near-field measurements. An exponentially tapered ridge in the rectangular waveguide and a novel waveguide transition were used for broadband impedance matching and suppression of higher order modes. The probe has broadband characteristics and its measured impedance bandwidth is approximately 123% (4.17:1) in the range 12.0-50 GHz for standing wave ratios (SWR) <3.0. The peak radiation gain range and nominal radar cross-section (RCS) are 5.7-14.3 dBi and -30 dBsm, respectively. The performance of this probe was verified using the measured results and is in good agreement with the simulated results.