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US 8,477,065 B2Granted
Combined transmit/receive single-post antenna for HF/VHF radar
AssigneeCodar Ocean Sensors, Ltd.
InventorsDonald E. Barrick, Peter M. Lilleboe
Life of this patent
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Abstract
An antenna configuration is described for high frequency (HF) or very high frequency (VHF) radars contained in a single vertical post. The radar may include a vertical dipole or monopole transmitting antenna collocated with a three-element receive antenna. The three antennas including two crossed loops and a vertical element are used in a direction-finding (DF) mode. Isolation between the three antennas produces high quality patterns useful for determining target bearings in DF mode. The single vertical post is sufficiently rigid mechanically that it may be installed along a coast without guy wires.
Claims20
An antenna system comprising:
- a first unit configured to receive HF or VHF radar signals, the first unit including:
- a first loopstick antenna including a first phase center and a first loopstick axis;
- and
- a second loopstick antenna including a second phase center and a second loopstick axis that is substantially orthogonal to the first loopstick axis;
- a second unit configured to transmit and receive HF or VHF radar signals, the second unit including:
- a first antenna including a third phase center, wherein the third phase center, the first phase center, and the second phase center are substantially collinear, the first antenna further including a first axis that is substantially orthogonal to the first loopstick axis and to the second loopstick axis;
- and
- a receiver module coupled to the first unit and to the second unit, the receiver module being configured to:
- receive a first receiver input signal from the first unit;
- receive a second receiver input signal from the second unit;
- and
- output a receiver output signal to the second unit.
9 more elements
An antenna system comprising:
- a first unit configured to receive HF or VHF radar signals, the first unit including:
- a first loopstick antenna including a first phase center and a first loopstick axis;
- and
- a second loopstick antenna including a second phase center and a second loopstick axis that is substantially orthogonal to the first loopstick axis;
- a second unit configured to transmit and receive HF or VHF radar signals, the second unit including:
- a first antenna including a third phase center, wherein the third phase center, the first phase center, and the second phase center are substantially collinear along a substantially vertical axis, the first antenna further including a first axis that is substantially orthogonal to the first loopstick axis and to the second loopstick axis;
- a conducting cylinder enclosing a first portion of the first antenna;
- and
- a decoupling device inside the conducting cylinder and surrounding a second portion of the first antenna, wherein the decoupling device is configured to decouple the first antenna from the conducting cylinder, the first loopstick antenna, and the second loopstick antenna;
- and
- a receiver module coupled to the first unit and to the second unit, the receiver module being configured to:
- receive a first receiver input signal from the first unit;
- receive a second receiver input signal from the first unit;
- and
- output a receiver output signal to the second unit.
12 more elements
An antenna system comprising:
- a first unit configured to receive HF or VHF radar signals, the first unit including:
- a first loopstick antenna including a first phase center, a first loopstick axis, a first core, and a first wire configured to form multiple turns around the first core;
- and
- a second loopstick antenna including a second phase center, a second loopstick axis that is substantially orthogonal to the first loopstick axis, a second core, and a second wire configured to form multiple turns around the second core;
- a second unit configured to transmit and receive HF or VHF radar signals, the second unit including:
- a dipole antenna including a third phase center, wherein the third phase center, the first phase center, and the second phase center are substantially collinear, the dipole antenna further including a first axis that is substantially orthogonal to the first loopstick axis and to the second loopstick axis.
3 more elements
Dependencies are inferred from the claim text.