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Researchers Submit Patent Application, "Rf Power Amplifier and Method of Assembly for Same", for Approval

September 10, 2014



By a News Reporter-Staff News Editor at Electronics Newsweekly -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventors CORREA, Paulo (Dana Point, CA); WIKE, Donald M. (Corona, CA); MOGILEVSKY, Leonid (Encino, CA), filed on February 21, 2013, was made available online on August 28, 2014.

The patent's assignee is Empower Rf Systems, Inc.

News editors obtained the following quote from the background information supplied by the inventors: "An RF power amplifier is a type of electronic amplifier used to convert a low-power radio-frequency signal into a larger signal of significant power, typically for driving the antenna of a transmitter. It is usually optimized to have high efficiency and high output power, while minimizing heat dissipation. The basic RF amplifier apparatus includes an input circuit, a splitter, a final stage and a combiner that operate together to deliver the amplified output.

"Existing RF amplifiers have problems. The RF amplifier assembly described above is difficult to manufacture, involves multiple assembly steps, and the assembly process is error prone. For example, each of the input signal circuit, splitter, modules of the final stage and combiner can be assembled on different printed circuit boards (PCBs). As such, wiring has to connect the circuitry together for the amplifier to operate. The circuitry and wiring of the RF amplifier can generate EMI that can affect the operation of the various electronic components of the circuit. Accordingly, the circuitry and wiring must be shielded and laid out on the circuit board in such a way so as to reduce RF and spurious emissions. Traditionally, this wiring is shielded by using a sheathed cabling to connect the various electronic components. However, the use of cabling creates significant routing and assembly issues and is difficult to implement. For example, the cabling can make the various solder connections difficult and time-consuming to implement. Moreover, the cabling and layout of the cabling for the traditional power amplifier has the potential to increase power losses on the wiring, reducing the overall efficiency of the power amplifier.

"In addition to the wiring issues, a heat sink must also be provided in the amplifier to dissipate the heat generated by the electronic components and wiring. The heat sink must be disposed to maximize the dissipation of heat generated by the electronics, while exposing the electronic components so that they can also receive EMI shielding. To do this, multiple layers are used to provide the heat sink and EMI shield. Because the devices can be highly irregular, each electronic component could have its own heat sink, printed circuit board and EMI shield, increasing the number of components in the assembly, and creating more wiring issues.

"Embodiments of the present invention attempt to resolve these issues and issues relating to combiners for RF power amplifiers."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "In accordance with the disclosed subject matter, various RF power amplifier architectures are disclosed.

"One embodiment of the invention is an RF power amplifier that comprises a controller, a driver, a splitter, a final stage, and a combiner coupled together to function as the RF power amplifier. One or more of the above components are arranged on one or more motherboards, e.g., a printed circuit board (PCB). A heat sink defines a base of the RF power amplifier, and in some embodiments the base includes at least two grooves formed therein, wherein the electrical components of the splitter and electrical components of the controller fit within one or more of the grooves so that these components can be substantially disposed within the heat sink. In some embodiments, a power rail is also provided, and is also disposed substantially within the heat sink. The power rail groove of the heat sink and the carrier of the final stage provide an EMI shield of the power rail.

"Other embodiments of the invention include an RF power amplifier architecture that comprises a motherboard printed circuit board (PCB), the motherboard PCB including electrical components for at least a splitter of the RF power amplifier; and a heat sink defining a base of the RF power amplifier, the heat sink including a groove. In some embodiments, the electrical components of the splitter and electrical components of a controller fit within the groove, and the heat sink serves as an EMI shield for RF and spurious emissions. In some embodiments, the RF power amplifier architecture is scalable and configurable without substantial design changes for RF power amplifiers over a range of frequencies and power levels.

"Another embodiment of the invention is a combiner for an RF amplifier. The combiner can include a ferrite core for low frequency operation, where the ferrite core has a hole defined therein. The combiner also includes a coaxial cable and a stripline. The coaxial cable is dimensioned to the highest operating frequency of the RF amplifier, and the coaxial cable has a first dielectric constant, wherein the coaxial cable connects an RF output of at least two final stages in parallel to the output of the RF amplifier, and the coaxial cable is routed through the hole of the ferrite core. The stripline has a second dielectric constant, and the stripline connects the RF output of the at least two final stages in parallel to the output of the RF amplifier. The stripline is routed around the ferrite core. In this embodiment, the electrical length of the stripline is matched to the electrical length of the coaxial cable, where the electrical length of the coaxial cable is defined by the first dielectric constant and the electrical length of the stripline is defined by the second dielectric constant. Another embodiment is a method for assembling a combiner for an RF amplifier, where the combiner has the features set forth above.

BRIEF DESCRIPTION OF THE DRAWING

"So that the features and advantages of the invention may be understood in more detail, a more particular description of the invention briefly summarized above may be had by reference to the appended drawings, which form a part of this specification. It is to be noted, however, that the drawings illustrate only various embodiments of the invention and are therefore not to be considered limiting of the invention's scope as it may include other effective embodiments as well.

"FIG. 1A is a block diagram of the RF amplifier according to an embodiment of the invention;

"FIG. 1B is a block diagram of the RF amplifier showing an input circuit/splitter board and the electronic components disposed thereon according to an embodiment of the invention;

"FIG. 1C is a block diagram of a small signal input circuit according to an embodiment of the invention;

"FIG. 1D is a block diagram of a driver amplifier according to an embodiment of the invention;

"FIG. 1E is a block diagram of a module of a final stage according to an embodiment of the invention;

"FIG. 1F is a block diagram of a combiner according to an embodiment of the invention;

"FIG. 1G is an equivalent circuit figure for the combiner shown in FIGS. 1F and 2D;

"FIG. 2A is a perspective view of a heat sink and electromagnetic field ('EMF') shield having corner brackets for bracing the heat sink and EMF shield into a case according to an embodiment of the invention;

"FIG. 2B is a perspective view of the heat sink and EMF shield having a printed circuit board ('PCB') disposed thereon according to an embodiment of the invention;

"FIG. 2C is a partially transparent top plan view of the PCB disposed on the heat sink and EMF shield according to an embodiment of the invention;

"FIG. 2D is an exploded, assembly view of the combiner according to an embodiment of the invention;

"FIG. 3 is a perspective view of the heat sink and EMF shield showing a portion of the PCB having components that generate heat and/or an EMF being disposed so as to be substantially encased by the heat sink and EMF shield according to an embodiment of the invention;

"FIG. 4A is a view of back panel assembly of an RF amplifier showing a plurality of fans for generating air flow through a portion of the heat shield and cover portions over various printed circuit boards according to an embodiment of the invention; and

"FIG. 4B is a view of the assembled RF amplifier showing a plurality of fans for generating air flow through a portion of the heat shield and cover portions over various printed circuit boards according to an embodiment of the invention."

For additional information on this patent application, see: CORREA, Paulo; WIKE, Donald M.; MOGILEVSKY, Leonid. Rf Power Amplifier and Method of Assembly for Same. Filed February 21, 2013 and posted August 28, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=5226&p=105&f=G&l=50&d=PG01&S1=20140821.PD.&OS=PD/20140821&RS=PD/20140821

Keywords for this news article include: Circuit Board, Electronic Components, Electronics, Empower Rf Systems, Empower Rf Systems Inc.

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Source: Electronics Newsweekly


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