In this paper high resolution SAR imaging results are presented, recorded with a compact 240 GHz radar sensor. The sensor is based on a fully integrated SiGe MMIC including on-chip antennas, allowing an ultra-compact, lightweight, and low energy sensor solution. The use of modern high-speed SiGe technology allows a high operating frequency reaching from 198 GHz to 250 GHz. While the power consumption of the whole sensor is 3.5 W, the overall size is given by 58x46x18 mm³, resulting in an remarkable small and energy efficient sensor. Additionally, a calibration technique is used to compensate the frequency response of the system, allowing a range resolution close to the theoretical limit given by the modulation bandwidth of up to 52 GHz. Combined with the large antenna beam, which gives a high resolution in cross-range direction, an ultra fine image quality can be achieved.
The article presents a monostatic D-band frequency-modulated continuous-wave (FMCW) radar based on a fully integrated monostatic single-channel silicon-germanium (SiGe) transceiver (TRX) chip. The chip is fabricated in Infineon's bipolar-complementary metal-oxide-semiconductor (BiCMOS) production technology B11HFC which offers heterojunction bipolar transistors (HBTs) with an f T / f max of 250 GHz/370 GHz. The monolithic microwave integrated circuits (MMICs) output signal is coupled by a fully differential substrate integrated waveguide (SIW) based coupling network. The output power at the WR-6.5 antenna flange is more than −10 dBm over a bandwidth of 37.5 GHz. For a sweep within a single-loop phase-locked loop (PLL) circuit from 174.5 to 121.5 GHz, a spatial resolution of almost 3 mm with a metallic plate as the target is achieved. The radar provides a small form factor of 2 × 4 × 5 cm 3 and low power consumption of 2.2 W at 5 V. Finally, the capabilities of the sensor for non-destructive testing (NDT) are demonstrated using a millimeter scanner. With radar imaging, it was possible to measure the orientation of the fiber layers up to a depth of 7.03 mm.
We discuss the determination of the Lamé parameters of an elastic material by the means of boundary measurements. We will combine previous results of Eskin-Ralston and Isakov to prove inverse results in the case of bounded domains with partial data. Moreover, we generalise these results to infinite cylinders.
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