Casilli to Present at International Microwave Symposium

Electrical engineering student Nicolas Casilli’s, E’21, MS’21, PhD’26, paper on “A UHF 1.3 cm 2 Passive Subharmonic Tag With a 13 m Read-Range” was accepted as one of the top-50 papers at the prestigious IEEE International Microwave Symposium IMS conference in San Diego. The paper will be presented during the Integrated RFID Systems and Applications Technical Session. Casilli is advised by ECE Assistant Professor Cristian Cassella.


This work reports on the design and performance of the first single-antenna subharmonic tag (SA-SubHT) of its kind. Thanks to the high-quality factor of its planar electrically small antenna (ESA) and to the advantageous nonlinear dynamics enabled by the adoption of two nonlinear components in its circuit, the reported SA-SubHT exhibits an exceptionally low-power threshold ( Pth = − 18 dBm). Such a low Pth -value is achieved regardless of the extraordinarily small size of the reported SA-SubHT (its area is only 1.3 cm 2 ), which has been built onto a 12.4 × 10.6 × 1.6 mm 3 FR-4 printed circuit board (PCB) and uses a ultrahigh-frequency (UHF) ESA occupying just 78 mm 2 . When using an effective isotropic radiated power (EIRP) at 890 MHz of + 36 dBm for its interrogation in an uncontrolled electromagnetic environment, the reported two-varactor SA-SubHT generates a subharmonic response at 445 MHz detectable from more than 13 m away from its interrogating device. This read-range exceeds by more than three times the distance the same SA-SubHT on an identical PCB covers when the second varactor is replaced by an equivalent linear capacitor with a nominal capacitance identical to the varactor’s zero-bias capacitance. The reported SA-SubHT creates new exciting possibilities to implement a fine-grained remote sensing through the deployment of a large number of SA-SubHTs.

Related Faculty: Cristian Cassella

Related Departments:Electrical & Computer Engineering