A Millimeter-Wave Low-Power Active Backscatter Tag for FMCW Radar Systems

• Published in: IEEE transactions on microwave theory and techniques Vol. 61; no. 5; pp. 1964 - 1972
• Main Authors: Strobel, A., Carlowitz, C., Wolf, R., Ellinger, F., Vossiek, M.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.05.2013; Institute of Electrical and Electronics Engineers
• Subjects: Amplifiers; Applied sciences; Backscatter; Chirp radar; Circuit properties; distance measurement; Electric, optical and optoelectronic circuits; Electronic circuits; Electronics; Exact sciences and technology; FM radar; frequency-modulated continuous-wave (FMCW) secondary radar; Integrated circuits; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; Oscillators; Oscillators, resonators, synthetizers; Power generation; Radar; Radio frequency; Radiolocalization and radionavigation; switched injection-locked oscillator (SILO); Switches; Telecommunications; Telecommunications and information theory; Tunable circuit; switched injection-locked oscillator (SILO); Frequency modulation; Chirp; Output power; Transponder; CW radar; Backscattering; Microwave; Amplifier; FM radar; Switching; Millimetric wave; Continuous wave; Phase coherence; frequency-modulated continuous-wave (FMCW) secondary radar; Chirp radar; Standard deviation; Distance measurement; Mean error; Low-power electronics; Measurement error; Injection locked oscillators; Backscatter
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2013.2252915

In this paper, a fully integrated active backscatter transponder based on the switched injection-locked oscillator (SILO) principle for frequency-modulated continuous-wave radar applications is presented. Furthermore, a method to characterize a SILO amplifier is extended and utilized to measure the system parameters of the presented backscatter tag that operates at 34.45 GHz. It is digitally tunable from 32.7 to 35.4 GHz and reaches an unpulsed output power of 5 dBm. Above injection power levels of -53 dBm, the SILO tag responds phase coherent at its maximum output power. In system measurements, the SILO backscatter transponder was used to perform distance measurements at ranges from 0.7 to 11.5 m. A remarkably good mean distance measurement error of 7 cm with a standard deviation of 10 cm was achieved in a strong multipath environment. The single measurement precision is below 3 mm.