Ground-penetrating imaging and detecting radar
US6522285B2 · kind B2 · utility
Inventors
Key dates
| Filing date | Mar 28, 2001 |
| Grant date | Feb 18, 2003 |
| Priority date | — |
| Expiry date | Mar 28, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S13/885
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A ground-penetrating radar comprises a single resonant microstrip patch antenna (RMPA) that is driven by a three-port directional coupler. A reflected-wave output port is buffered by a wideband isolation amplifier and a reflected-wave sample is analyzed to extract measured values of the real and imaginary parts of the load impedance-the driving point impedance of RMPA. Each such port will vary in a predictable way according to how deeply an object is buried in the soil. Calibration tables can be empirically derived. Reflections also occur at the interfaces of homogeneous layers of material in the soil. The reflected-wave signals are prevented from adversely affecting transmitted-signal sampling by putting another wideband isolation amplifier in front of the input port of the directional coupler. A suppressed-carrier version of the transmitted signal is mixed with the reflected-wave sample, and the carrier is removed. Several stages of filtering result in a DC output that corresponds to the values of the real and imaginary parts of the load impedance. The suppressed-carrier version of the transmitted signal is phase shifted 0° or 90° to select which part is to be measured at…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.