Patent Application
20220140481
The present invention generally relates to radio frequency (RF) communications hardware. More particularly, the present invention relates to antenna systems.
In many global navigation satellite system (“GNSS”) antenna applications, it is beneficial for a radiation pattern of an antenna to have a broad beamwidth. In particular, it is beneficial for the antenna to provide hemispheric coverage centered about the zenith and for a gain of the antenna to be as high as possible near the horizon without significant gain loss at or near the zenith while maintaining the gain as low as possible below the horizon.
However, known antenna systems that provide the above-identified features suffer from several known drawbacks. For example, some known antenna systems provide the broad beamwidth by employing an antenna element with a large height dimension that is not suitable for applications requiring antennas with low physical profiles. Furthermore, other known antenna systems require the use of resistors, capacitors, and/or inductors to create a loading circuit. Regardless, all of these known antenna systems require a large volume or additional loading components to implement and only broaden the beamwidth by a small degree.
In view of the above, there is a continuing, ongoing need for improved antenna systems.
While this invention is susceptible of an embodiment in many different forms, there are shown in the drawings and will be described herein in detail specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention. It is not intended to limit the invention to the specific illustrated embodiments.
Embodiments disclosed herein can include an antenna system that can produce a radiation pattern with a broad beamwidth, hemispheric coverage centered about the zenith, and a gain as high as possible near the horizon without significant gain loss at or near the zenith while maintaining the gain as low as possible below the horizon.
In some embodiments, the antenna system disclosed herein can include a ground plane, an antenna disposed on a top side of the ground plane and configured to produce a radiation pattern, and a plurality of parasitic elements connected or coupled to and extending from the top side of the ground plane and positioned around the antenna. For example, in some embodiments, a respective proximate end of each of the plurality of parasitic elements can be connected to the ground plane, and a respective distal end of each of the plurality of parasitic elements can be displaced from the ground plane.
In some embodiments, each of the plurality of parasitic elements can be positioned at a uniform distance from a center of the antenna, and in some embodiments, each of the plurality of parasitic elements can be oriented at a common pitch angle relative to the ground plane. However, in any embodiment, a respective length of each of the plurality of parasitic elements, the common pitch angle, and/or the uniform distance can be optimized in order to broaden a beamwidth of the radiation pattern. For example, in some embodiments, the uniform distance can be equal to one quarter of a wavelength (λ/4) of a frequency of the antenna. Additionally or alternatively, in some embodiments, the respective length of each of the plurality of parasitic elements can be between approximately 0.2 and approximately 0.25 times the wavelength of the frequency of the antenna. Additionally or alternatively, in some embodiments, the common pitch angle can be between approximately 35° and approximately 55°, and in some embodiments, the common pitch angle can be approximately 45°.
In some embodiments, the plurality of parasitic elements can include any number of elements as would be known by one of ordinary skill in the art, for example, between 6 and 16 elements. Additionally or alternatively, in some embodiments, a respective top section of each of the plurality of parasitic elements can be bent downwards or inwards towards the ground plane to reduce a respective height of each of the plurality of parasitic elements relative to the ground plane.
In some embodiments, the plurality parasitic elements can be shaped and oriented in a manner that is appropriate for and/or complementary to a polarization of the antenna's radiation. For example, in embodiments in which the radiation is right hand circularly polarized (RHCP), the plurality of parasitic elements can include helical-shaped elements, and the respective distal end of each of the plurality of parasitic elements can extend in a counter-clockwise direction relative to the respective proximate end of a respective one of the plurality of parasitic elements. Alternatively, in embodiments in which the radiation is left hand circularly polarized (LHCP), the plurality of parasitic elements can include helical-shaped elements, and the respective distal end of each of the plurality of parasitic elements can extend in a clockwise direction relative to the respective proximate end of the respective one of the plurality of parasitic elements. However, embodiments disclosed herein are not so limited and can include additional or alternative embodiments in which, for example, the plurality of parasitic elements can be vertical and/or the plurality of parasitic elements can include non-curving, straight elements.
As seen in
Additional or alternative embodiments for both the antenna 22A and the plurality of parasitic element 22A are contemplated. For example,
The antenna system 20B of
Furthermore, the antenna system 20C of
Further still, the antenna system 20E of
Although a few embodiments have been described in detail above, other modifications are possible. For example, other components may be added to or removed from the described systems, and other embodiments may be within the scope of the invention.
From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific system or method described herein is intended or should be inferred. It is, of course, intended to cover all such modifications as fall within the spirit and scope of the invention.
