Short range micro-power impulse radar with high resolution swept range gate with damped transmit and receive cavities

A radar for detecting characteristics of objects within a field, comprising:

• a transmitter, including a shielded transmit cavity having a transmit opening with a perimeter and facing the field, and a transmit antenna within the shielded transmit cavity, which transmits a sequence of electromagnetic signals from the transmit antenna into the field in response to a transmit timing signal, each of the signals in the sequence having a duration of about 10 nanoseconds or less;
• a receiver, including a shielded receive cavity having a receive opening with a perimeter and facing the field, and a receive antenna within the shielded receive cavity, which samples echoes from objects in the field of the sequence of electromagnetic signals with controlled timing, in response to a receive timing signal, and generates a sample signal in response to the samples;
• a shielding base, supporting the shielded transmit cavity and the shielded receive cavity such that the transmit cavity is separated from the receive cavity, and shielding receiver and transmitter electronics;
• and
• a timing circuit, shielded by the shielding base, which supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver, such that a sampling interval between transmission of a given electromagnetic signal in the sequence and sampling of echoes of said given electromagnetic signal has a length of less than about 300 nanoseconds.

A method for sensing characteristics of objects within a field, comprising:

• transmitting a sequence of electromagnetic signals into the field from a transmit cavity with controlled timing, wherein electromagnetic signals in the sequence have a duration of about 10 nanoseconds or less, and a transmit interval between electromagnetic signals in the sequence has a length which exceeds 100 nanoseconds;
• sampling, at a receive cavity adjacent the transmit cavity with controlled timing, a sequence of echoes of the sequence of electromagnetic signals reflected from objects within the field, each echo in the sequence sampled within a sampling interval of time of less than 100 nanoseconds from the time of transmission of a corresponding electromagnetic signal in the sequence;
• connecting means for reducing clutter in the sampled signal to the receive and transmit cavities prior to the steps of transmitting and sampling;
• and
• processing the sampled sequence of echoes to indicate a characteristic of an object within the field.