Patent ID: 8031109

Claim:
An antenna system configured to transmit and receive radar signals, the antenna system comprising: a compact receive unit configured to receive HF or VHF radar signals, the compact receive unit including: a first loopstick antenna having a first phase center and a first loopstick axis; and a second loopstick antenna having a second phase center and a second loopstick axis that is substantially orthogonal to the first loopstick axis; wherein the compact receive unit is disposed within a receive unit enclosure that is hermetically sealed; a transmit/receive unit configured to transmit and receive the HF or VHF radar signals, the transmit/receive unit including: a substantially vertical transmit/receive antenna having: a transmit/receive phase center, wherein the transmit/receive phase center, the first phase center, and the second phase center are substantially collinear along a substantially vertical axis; and a transmit/receive axis that is substantially orthogonal to the first loopstick axis and to the second loopstick axis; a conducting cylinder enclosing at least a portion of the substantially vertical transmit/receive antenna; and at least one decoupling device inside the conducting cylinder and surrounding a portion of the substantially vertical transmit/receive antenna to decouple the substantially vertical transmit/receive antenna from the conducting cylinder and from the loopstick antennas; and a receiver module coupled to the compact receive unit and to the transmit/receive unit, the receiver module being configured to: receive a first receiver input signal from the compact receive unit; receive a second receiver input signal from the transmit/receive unit; and output a receiver output signal that is amplified and is inputted to the transmit/receive unit.