Wideband Low-Loss Rectangular-to-Circular Coaxial Transition Within DC-80 GHz

This conference presents a rectangular-to-circular coaxial transition with low-loss property and compact structure. The required impedance matching is achieved by three cylinders with different sizes. Moreover, three chamfered structures are analyzed to compensate for the parasitic capacitance. The simulated results show that the designed transition structure has a return loss better than 42 dB from DC to 80 GHz and insertion loss better than 0.028 dB below 80 GHz. The characteristic impedance of the rectangular to circular coaxial transition is well matched to 50
$\Omega$
, facilitating for the measurement applications of some components.