Patent Application
20150250068
Existing wireless base stations use band-rejection filters to permit the transmission and reception of some radio frequencies and attenuate or prohibit others.
In addition, band-rejection filters also function to carry some loads, such as a mechanical load (e.g., weights) and loads due to the force of winds. However, traditional band-rejection filters are very sensitive to vibrations and other forces that result from carrying a load. For example, an external force may change the physical structure of the filter which, in turn, may change the electrical function and performance of the filter because a traditional filter has a steep roll off at its attenuated frequencies. Said another way, if the physical structure of the filter is changed, the frequencies that it may attempt to pass or attenuate may change as well. In effect, the filter will become detuned and unreliable because it will attempt to pass undesirable frequencies.
Exemplary embodiments of methods and devices for protecting band rejection filters from external forces are provided.
According to an embodiment, a band rejection filter apparatus (i.e., device) may comprise: an electrical filter section configured to receive a first range (e.g. 698 to 805 MHz) of radio frequency (RF) signals, and to output a second range (e.g., 698 to 715 and/or 728 to 805 MHz) of RF signals that is a subset of the first range of RF signals; a frame configured to support the electrical filter section; and a plurality of dampers connected to the frame, and operable to reduce the effects of external forces applied to the frame or electrical filter section. In addition, the filter apparatus may comprise one or more connectors, each connector configured to be connected to the frame on one side and to the external load (e.g., base station transceiver) on a second side.
In one embodiment one or more of the dampers may comprise an elastomer damper (e.g., rubber dampers), or, alternatively, a mechanical spring, (e.g., 0.5 inch diameter spring) or a combination of the two types of dampers.
In other embodiments the frame may comprise an aluminum frame. Still further, in yet further embodiments each one of the plurality of dampers may be connected to a side of the frame, or, alternatively, to a different side of the frame. The dampers may be the same size, or alternatively may be different sizes. For example, in one embodiment, at least one of the plurality of dampers is smaller in size than a remainder of the dampers. In addition to the apparatuses described above and herein exemplary, related methods are also provided.
In one embodiment an exemplary method may comprise: receiving a first range of radio frequency (RF) signals, and outputting a second range of RF signals that is a subset of the first range of RF signals, from a band rejection electrical filter section; supporting the filter section using a frame (e.g., aluminum frame); and reducing the effects of external forces applied to the frame or filter section using a plurality of dampers connected to the frame. The first range may comprise a range of 698 to 805 MHz while the second range may comprise a range of 698 to 715 MHz and/or 728 to 805 MHz. The frame may be connected to a base station transceiver.
This method may further comprise further reducing the effects of external forces applied to the frame or filter section using one or more connectors, each connector configured to be connected to the frame on one side and to the external load on a second side.
As explained previously, the one or more of the dampers may comprise an elastomer (e.g., rubber), or a mechanical spring or a combination of the two types of dampers, and each one of the plurality of dampers may be connected to a different side (or same side) of the frame. Yet further, at least one of the plurality of dampers may be a different size (e.g., smaller) than a remainder of the dampers.
Additional features of the inventions will be apparent from the following detailed description and appended drawings.
FIGS 1a and 1b depict an exemplary band rejection filter apparatus according to exemplary embodiments of the invention.
a through 2c depict different views of an exemplary band rejection filter apparatus with dampers according to embodiments of the invention.
Exemplary embodiments for protecting band rejection filters, used in wireless base stations, from external factors are described herein and are shown by way of example in the drawings. Throughout the following description and drawings, like reference numbers/characters refer to like elements.
It should be understood that, although specific exemplary embodiments are discussed herein there is no intent to limit the scope of present invention to such embodiments. To the contrary, it should be understood that the exemplary embodiments discussed herein are for illustrative purposes, and that modified and alternative embodiments may be implemented without departing from the scope of the present invention. Further, though specific structural and functional details may be disclosed herein, these are merely representative for purposes of describing the exemplary embodiments.
It should be noted that one or more exemplary embodiments may be described as a process or method. Although a process/method may be described as sequential, it should be understood that such a process/method may be performed in parallel, concurrently or simultaneously. In addition, the order of each step within a process/method may be re-arranged. A process/method may be terminated when completed, and may also include additional steps not included in a description of the process/method.
As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural form, unless the context indicates otherwise.
As used herein, the term “embodiment” refers to an embodiment of the present invention.
In accordance with embodiments of the present invention, band rejection filters are protected or isolated from the effects of external forces, such as mechanical loads and wind. This may be achieved by “cocooning” or otherwise surrounding (either fully or partially) a band rejection filter with a frame, and supporting the frame and filter with vibration and shock absorbing components. The absorbing components may be of various design, such as elastomers or springs though other equivalent components may be used. Such a frame assists and relieves the filter from carrying an external load.
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In accordance with additional embodiments, the frame 3 may designed to be structurally strong to the weight of the filter section 2 and the external load 6. In the case of an RRH, that may be 50 lbs. Besides the weight of an RRH, the frame 3 and connectors 5 may be operable to withstand forces from winds as high as 200 miles per hour without imparting external forces (stresses, strains, vibration, etc.) on the filter section 2. Accordingly, detuning of the filter section 2 may be prevented.
While exemplary embodiments have been shown and described herein, it should be understood that variations of the disclosed embodiments may be made without departing from the spirit and scope of the claims that follow.
