Communications: radio wave antennas – Antennas – Spiral or helical type
Reexamination Certificate
1999-12-22
2001-10-09
Wong, Don (Department: 2821)
Communications: radio wave antennas
Antennas
Spiral or helical type
C343S855000
Reexamination Certificate
active
06300918
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to a phased array antenna including a plurality of spiral arm antenna elements and, more particularly, to a phased array antenna including a plurality of hexagonal shaped, spiral arm antenna elements arranged in concentric rings, where the ends of the arms of diagonally adjacent antenna elements are positioned relative to each other to provide element-to-element coupling to increase the antennas bandwidth.
2. Discussion of the Related Art
Modern tactical military aircraft require radio communications over several frequency bandwidths and communication modes to support the communications, navigation and identification (CNI) functions necessary for operation of the aircraft. These radio frequency (RF) bandwidths generally include the VHF frequency modulation (FM) band (30-88 MHz), the VHF amplitude modulation (AM) band (118-174 MHz) and the UHF band (225-400 MHz). These aircraft also typically include satellite communications systems that support military command, control, communications and intelligence (C
3
I) functions. These satellite communications signals typically are in the 1-20 GHz frequency range (X, Ku, L-bands).
Suitable antenna systems are necessary to support the various CNI and C
3
I functions on the aircraft over the several frequency bands of interest. For the high frequency satellite communications functions, a low cost, wideband antenna that supports a plurality of high frequency, circularly-polarized antenna beams is necessary. Common gimbaled, parabolic dish antennas are sufficient to support most of the satellite communications functions for the antenna beams at these frequencies. Such dish antennas are known to be mounted on aircraft, or other vehicles, at a suitable location where a large radome is used to cover the parabolic dish.
The known dish antennas for satellite communications functions have a number of drawbacks when used in military applications, particularly on aircraft. These drawbacks include the fact that a dish antenna is generally limited to only receiving and/or transmitting one antenna beam at any given time. Thus, multiple high gain dish antennas are necessary to support the several satellite communications frequencies. Additionally, wideband circularly-polarized dish antenna feeds are very costly and suffer from poor RF performance. More importantly, modern warfare surface ships, aircraft, and command and control vehicles must have a low radar cross section (RCS), or radar signature, to survive in hostile warfare environments. One or more dish antennas mounted on an aircraft or other military vehicle significantly increases the RCS of the vehicle, making the use of the non-conformal dish antennas undesirable in the warfare environment.
What is needed is a suitable satellite communications antenna for use on military vehicles that is low cost, has a wide bandwidth, simultaneously supports a plurality of antenna beams, and has a low RCS. It is therefore an object of the present invention to provide such an antenna system.
SUMMARY OF THE INVENTION
In accordance with the teachings of the present invention, a phased array antenna is disclosed that includes a plurality of inter-coupled multiple arm spiral antenna elements. The antenna elements are hexagonal in shape and are positioned in a triangular lattice geometry, where the elements are arranged in rings around a common center element. The elements include at least two arms which terminate at opposite sides of the element. The ends of the arms of diagonally adjacent elements are positioned proximate to each other to provide inter-element coupling to increase the bandwidth of the antenna. The tight coupling of the antenna elements also reduces the RCS of the antenna. The antenna is made using conformal load-bearing antenna structure manufacturing technologies to reduce the RCS of the vehicle on which the antenna is mounted.
Additional objects, advantages and features of the present invention will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 3787871 (1974-01-01), Reese
patent: 3925784 (1975-12-01), Phelan
patent: 4114164 (1978-09-01), Greiser
patent: 4458248 (1984-07-01), Lyasko
patent: 4656485 (1987-04-01), Werner et al.
patent: 5223849 (1993-06-01), Kasevich et al.
patent: 5933121 (1999-08-01), Rainhart et al.
Goetz Allan C.
Riddle Robert G.
Dinh Trinh Vo
Harness & Dickey & Pierce P.L.C.
TRW Inc.
Wong Don
LandOfFree
Conformal, low RCS, wideband, phased array antenna for... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Conformal, low RCS, wideband, phased array antenna for..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Conformal, low RCS, wideband, phased array antenna for... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2572626