Superconducting Microstrip-Fed Antenna; Coupled to a Microwave Kinetic Inductance Detector

A proper antenna to couple to a microstrip Microwave Kinetic Inductance Detector (MKID) is designed and simulated. A twin-slot microstrip-fed inline antenna is designed for frequency band of 600-720~GHz integrated with an elliptical lens and coupled to the MKID. A systematic design procedure for design of such antenna with microstrip inline feeding is presented. Whole structure of lens and twin slot is simulated by full-wave electromagnetic numerical software. A locally changing technique is also used to have good matching between antenna and feed line. Results show good radiation pattern with directivity near 30dB and side lobe levels better than -10.5 dB in both H-plane and E-plan and also antenna efficiency is better than 93% and total coupling efficiency is better than 84% in whole frequency band. This antenna is recently used in a superconducting on-chip sub-millimeter wave filterbank spectrometer.