Patent Application
20060116071
The present invention relates generally to antenna systems for satellite digital audio radio service communications and more specifically to an antenna module incorporated into a receiver for satellite digital audio radio service communications.
Communications between terrestrial devices such as radios and earth-orbiting satellites are well known. A commercial application of these satellite systems is satellite digital audio radio service (SDARS). SDARS systems broadcast high quality uninterrupted audio through satellites and earth-based stations. SDARS systems typically include an antenna with a low-noise amplifier and a receiver. The antenna initially receives encoded signals from the satellites and/or terrestrial transmitters. The amplifier, which is conventionally housed within the antenna, amplifies the received signal. The receiver decodes the transmitted signal and provides the signal to the radio.
SDARS antenna is housed external to the receiver and connectable to the receiver via a removable conductor, such as a coaxial cable having adapters on each end. In an automobile environment, for example, the receiver may be located in the trunk area while the antenna is located on the roof. The receiver is then coupled to the antenna via the coaxial cable that is routed throughout the vehicle. The intrinsic properties of the wire degrade the amplitude of the satellite signal that travels from the antenna to the receiver. Accordingly, the amplifier is required in order to compensate for the amplitude losses. As such, the amplifier, the conductor having couplers, and the couplers associated with the receiver and antenna substantially increase manufacturing and overall system costs. Additionally, design time, packaging considerations, and system efficiency are negatively impacted by the requisite components of the conventional system. The above considerations have also inhibited the ability of designers to provide smaller portable SDAR receiving systems.
The embodiments described hereinafter were developed in light of these and other disadvantages of existing SDARS receiving systems.
In light of the above disadvantages of conventional systems, a receiver system for receiving satellite digital audio radio signals is disclosed. The receiver system includes a receiver and an antenna module that is permanently coupled and/or integrated with the receiver.
Referring to
Referring to
Regarding the permanently connected components within the antenna module 14, the antenna element 16 initially receives an encoded signal from the satellite and/or a terrestrial transmitter (not shown). Antenna element 16 may be a quadrifilar helical antenna or a patch antenna. As well-known in the art, the quadrifilar helical antenna and patch antenna typically possess different gain patterns. Thus, depending upon performance requirements, the quadrifilar helical antenna may be preferred over the patch antenna or vice versa. In the case that the antenna element 16 is a quadrifilar helical antenna, a capacitively loaded dielectric may be utilized for frequency tuning purposes. The dielectric may have a dielectric constant in the range of 2.0 to 9.0. As known in the art, the dielectric also reduces the size of the antenna element 16. Furthermore, utilizing a quadrifilar helical antenna enables improved reception of signals transmitted by terrestrial transmitters.
The amplifier 22 (
The ground plane 18 provides a radio frequency ground for the antenna element 16. Although the ground plane 18 is shown as a discrete component, the ground plane 18 may be integrated into the antenna element 16 by soldering or any other conventional technique. Alternatively, the housing 12 may serve as a ground plane for the antenna element 16. Integrating the ground plane 18 into the antenna element 16 or the housing 12 further reduces the packaging size of the antenna module 14.
Coupled to the ground plane 18 may be the antenna feeder 20. The feeder 20 energizes the antenna element 16. Where the quadrifilar helical antenna serves as the antenna element 16, the feeder 20 may be a four port hybrid coupler or alternatively a phasing network. As well-known in the art, the four port hybrid coupler and phasing network are capable of energizing the antenna element 16 in phase quadrature.
Referring to
The receiver 10 may also include a port 11. The port 11 provides a connection point between the receiver 10 and other devices such as a power source, a computer, or other receivers. By way of the port 11, the receiver 10 may receive power, data, and software upgrades.
The antenna module 14 may be permanently coupled thereto and/or integrated with the receiver 10 at various locations. The components that comprise the antenna module 14 may be integrated onto a printed circuit board and incorporated into the receiver 10. As shown in
Referring to
The antenna module 24 may be mechanically attachable to the receiver 10 by molding a stub (not shown) onto the housing 12 that corresponds in size with an aperture (not shown) that is molded into the antenna module 24. Incorporating multiple antenna modules into the receiver system enables the antenna modules 14 and 24 to operate in a diversity scheme. Typically, the antenna modules 14 and 24 have a plurality of available pre-programmed channels on which to receive satellite signals. Accordingly, the software embedded within the receiver 10 is capable of determining the channels that provide the best reception on each antenna module 14 and 24. The receiver 10 may then utilize those identified channels thereby providing the user with optimum reception. This process of identifying the channels for optimum reception is known as diversity scheme operation.
As noted above, the antenna module 24 may be moveable about the housing 12. For instance, in areas of weak signal reception, the user can pivot the antenna module 24 about the housing 12 thereby improving signal reception. Alternatively, the user may detach the antenna module 24 from the receiver 10 thereby improving signal reception. Where the antenna module 24 is detachable, the patch antenna is typically preferred for use as the antenna element 16 because of the reduced size and gain characteristics of the patch antenna.
As illustrated, the amplifier 22, the antenna element 16 and other operational components may be permanently coupled to the receiver 10. Because the antenna module 14 is permanently coupled to the receiver 10, the use of a conductor and associated couplings that couple the antenna module 14 and the receiver 10 are not required. The elimination of the conductor also reduces the level of signal amplification required. Accordingly, in one embodiment the amplifier 22 is also not needed. Alternatively, where the amplifier 22 is required, a less powerful amplifier may be utilized. Thus, the size of the amplifier and costs associated with the amplifier are reduced. Accordingly, the receiver 10 may operate in a vehicle environment and/or a stand-alone portable SDARS receiving system.
Various other modifications to the present invention may occur to those skilled in the art to which the present invention pertains. Other modifications not explicitly mentioned herein are also possible and within the scope of the present invention. It is the following claims, including all equivalents, which define the scope of the present invention.
