Ground-penetrating radar scanner with balanced UWB directional coupler

A ground-penetrating radar (GPR) scanner for investigating a sub-surface, the GPR scanner comprising

• an antenna assembly configured for transmitting and receiving ultra-wide band (UWB) signals,
• a directional coupler,
• a UWB signal generator configured for providing outgoing UWB signals through the directional coupler to the antenna assembly,
• a UWB signal sampling unit configured for receiving incoming UWB signals from the antenna assembly through the directional coupler, and
• an impedance,
• wherein the directional coupler is configured as a balanced UWB directional coupler and comprises:
• a first port configured for receiving positive outgoing UWB signals from the UWB signal generator,
• a second port configured for receiving negative outgoing UWB signals from the UWB signal generator, the second port being balanced with the first port,
• a third port and a fourth port both connected to the impedance, the fourth port being balanced with the third port,
• a fifth port configured for outputting the positive outgoing UWB signals to the antenna assembly and for receiving positive incoming UWB signals from the antenna assembly,
• a sixth port configured for outputting the negative outgoing UWB signals to the antenna assembly and for receiving negative incoming UWB signals from the antenna assembly, the sixth port being balanced with the fifth port,
• a seventh port configured for outputting the positive incoming UWB signals to the UWB signal sampling unit, and
• an eighth port configured for outputting the negative incoming UWB signals to the UWB signal sampling unit, the eighth port being balanced with the seventh port.