Highly Sensitive Defect Detectors and Comparators Exploiting Port Imbalance in Rat-Race Couplers Loaded With Step-Impedance Open-Ended Transmission Lines - Herrojo, Cristian; Velez, Paris; Munoz-Enano, Jonathan; Su, Lijuan; Casacuberta, Pau; Barba, Marta Gil; Martin, Ferran; (Ieee Sensors Journal, 2021)