Patent Application
20250192067
The present disclosure relates to RF components with integrated EMI shielding, and more particularly, to a diplexer with integrated EMI shielding for use in an RF amplifier.
RF amplifiers are used to amplify RF (radio frequency) signals in communication systems, such as a CATV system that provides both downstream (forward) signals to subscriber locations and upstream (reverse) signals from subscriber locations. In a hybrid fiber-coaxial (HFC) network providing CATV services, for example, optical communication is provided over optical fibers between a headend/hub and an optical node and electrical RF communication is provided over coaxial cables between the optical node and the subscriber locations. In such HFC networks, RF amplifiers are used after the optical node to extend the transmission distance of the RF signals and thus extend the reach of the CATV services provided to subscriber locations.
As the bandwidth of communication systems continues to increase and the RF amplifiers are required to handle higher frequencies (e.g., up to 1.8 GHZ), electromagnetic interference (e.g., cross-talk and RF leaking) becomes a bigger problem. Providing EMI shielding of components in the RF amplifier presents challenges, especially given the limited space within the amplifier housings and on the circuit boards in the RF amplifiers. An example of RF components that may need to be shielded includes the diplexers (also referred to as diplex filters) used in the RF amplifier to separate forward and reverse RF signals for amplification in the RF amplifier.
Consistent with one aspect of the present disclosure, an RF amplifier includes an amplifier chassis and amplifier circuitry supported by the amplifier chassis and coupled to an RF signal path. The amplifier circuitry includes at least one RF component for receiving at least one RF signal carried on the RF signal path. The at least one RF component includes a component housing made of a dielectric material, an RF component circuit at least partially disposed in the component housing, and an EMI shield. The EMI shield includes a shielding portion located in the component housing and spaced from the RF component circuit. The EMI shield also includes engaging members extending from the shielding portion inside the component housing to outside of the component housing. The engaging members contact the amplifier chassis for securing the RF component to the amplifier chassis and for grounding the EMI shield to the amplifier chassis.
Consistent with another aspect of the present disclosure, an EMI-shielded diplexer includes a housing made of a dielectric material, a diplexer circuit at least partially disposed in the housing, and an EMI shield. The EMI shield includes a shielding portion located in the housing and spaced from the diplexer circuit. The EMI shield also includes engaging members extending from the shielding portion inside the housing to outside of the housing. The engaging members are configured to contact a chassis that receives the diplexer for securing the diplexer to the chassis and for grounding the EMI shield to the chassis.
These and other features and advantages will be better understood by reading the following detailed description, taken together with the drawings wherein:
An RF component with integrated EMI shielding, consistent with the present disclosure, may be used in an RF amplifier. The RF component includes a component housing made of a dielectric material, an RF component circuit, and an EMI shield integrated with the component housing for shielding the RF component circuit. The EMI shield may include a shielding portion located in the component housing and spaced from the RF component circuit by a predetermined distance and engaging members extending from the shielding portion inside the component housing to outside of the component housing. The engaging members contact an amplifier chassis for securing the RF component to the amplifier chassis and for grounding the EMI shield to the amplifier chassis. One example of the RF component includes a diplexer.
The RF component with integrated EMI shielding may be used in an RF amplifier, such as a line extender (LE) amplifier in a hybrid fiber-coaxial (HFC) network providing CATV services. Such an RF amplifier may be capable of amplifying RF signals up to 1.8 GHz. At those higher frequencies (e.g., 1.8 GHz or higher) RF cross-talk and leaking may be problem in the RF components, such as diplexers, that receive the RF signals. Previous attempts at shielding the diplexers have involved adding an extra layer of metal on top of the diplexer housing. These separate shields must be unscrewed to access the diplexer and may be lost and/or not reinstalled properly when a technician in the field is troubleshooting the amplifier. Providing an integrated EMI shield may provide improved EMI shielding by shorting unnecessary RF signals to ground (e.g., to the amplifier chassis) while also allowing the EMI shield to be removed together with the diplexer (or other shielded RF component) as a single unit. One challenge with an integrated EMI shield is locating the EMI shield relative to the RF component circuit (e.g., the diplexer circuit) to short the unnecessary RF signals without shorting the useful RF signals.
As used herein, the term “coupled” refers to any connection, coupling, link or the like between elements. Such “coupled” elements are not necessarily directly connected to one another and may be separated by intermediate components.
Referring to
As shown in greater detail in
The shielding portion 132 and the engaging portions 134 may be formed as one piece from a conductive material, such as stainless steel or phosphor bronze, capable of providing the EMI shielding. In the illustrated embodiment, the shielding portion 132 has a substantially flat configuration and shape that conforms to the inside of the body 112 of the housing 110. The shielding portion 132 may be spaced as far as possible from the RF component circuit 120 to prevent the EMI shield 130 from creating a capacitance effect and shorting useful RF signals. In one example, the shielding portion 132 is spaced from the RF component circuit 120 at a distance in a range of about 0.625 in. to 1 in. As shown in
In the illustrated embodiment, the engaging members 134 have a leaf spring configuration including a first portion 135 extending from the shielding portion 132 and a second portion 136 folded back against the first portion 135. The second portion 136 has a bend 137 that protrudes and engages the amplifier chassis, as will be described in greater detail below. This shape and configuration allows the engaging members 134 to be spring-biased against the chassis to secure the RF component 100 and to provide sufficient electrical contact for grounding. Other types and configurations of engaging members are also contemplated and within the scope of the present disclosure.
The RF component circuit 120 may include circuit components 122 on a circuit board 124 and electrical contacts 126 extending from the circuit components 122 and the circuit board 124, for example, for electrically connecting to amplifier circuitry. In the illustrated embodiment, the circuit board 124 of the RF component circuit 120 is supported at the open end 118 of the component housing 110 such that the circuit components 122 are inside the body 112 of the housing 110 and the electrical contacts 126 (e.g., pins) extend from the open end 118 of the housing 110. The circuit board 124 may be supported by a portion 119 of the housing 110 proximate the open end 118, as shown in
Referring to
As shown schematically in
As shown in
Accordingly, an RF component with integrated EMI shielding, consistent with embodiments of the present disclosure, improves EMI shielding of an RF component, such as a diplexer, in an RF amplifier without requiring a separate EMI shield on top of and covering the RF component.
While the principles of the invention have been described herein, it is to be understood by those skilled in the art that this description is made only by way of example and not as a limitation as to the scope of the invention. Other embodiments are contemplated within the scope of the present invention in addition to the exemplary embodiments shown and described herein. Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention, which is not to be limited except by the following claims.
