System and method for frequency equalization and temperature compensation in a radio frequency device - Patents.com

Abstract

A frequency equalizer is provided, comprising a coupler having a main segment extending between a first port and a second port and a coupling segment disposed in coupling relationship with the main segment and extending between a third port and a fourth port. The frequency equalizer further comprises a first thermistor electrically coupled in series between the first port and an input line, a second thermistor electrically coupled in series between the second port and an output line, and a first shunt resistor coupled through the third port. The frequency equalizer simultaneously achieves frequency equalization and temperature compensation for signals transmitted through the frequency equalizer.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Patent Application No. 62 / 936,720, filed November 18, 2019, the entire disclosure of which is incorporated herein by reference as part of this application. [Background technology]

[0002] TECHNICAL FIELD Embodiments described herein relate generally to radio frequency (RF) interconnects, and more particularly to frequency equalization and temperature compensation in RF devices.

[0003] RF devices are used for many applications such as remote communications and remote sensing. The performance of such devices, for example, their ability to produce a desired output signal for a given input signal, can be affected by many different factors such as the frequency of the input signal and the temperature of the RF device. For example, the attenuation of an RF signal generally increases as the frequency of the RF signal increases. Furthermore, as temperature increases, the attenuation of an RF signal generally increases. These interactions can be undesirable because RF devices generally need to perform relatively consistently over a particular frequency range and / or temperature range. However, adding compensation circuitry can increase the component, manufacturing and installation costs of the RF device and, if installed, can occupy additional physical space in the RF application. Thus, circuits that provide improved frequency equalization and temperature compensation are desirable. Summary of the Invention

[0004] In one aspect of the present invention, a frequency equalizer is provided. The frequency equalizer includes a coupler having a main segment extending between a first port and a second port, and a coupling segment disposed in a coupling relationship with the main segment and extending between a third port and a fourth port. The frequency equalizer further includes a first thermistor electrically coupled in series between the first port and an input line, a second thermistor electrically coupled in series between the second port and an output line, and a first shunt resistor coupled through the third port. The frequency equalizer simultaneously achieves frequency equalization and temperature compensation for signals transmitted through the frequency equalizer.

[0005] In another aspect of the invention, an electronics package for a frequency equalizer is provided, the electronics package comprising a substrate having a first surface and a second surface, a ground plane disposed on the second surface, and a coupler having a main segment defined by a main strip disposed on the first surface and the ground plane as described above. The main segment extends between a first port and a second port. The coupler further comprises a coupling segment defined by a coupling strip disposed on the second surface and the ground plane. The coupling segment is disposed in coupling relationship to the main segment and extends between a third port and a fourth port. The electronics package further comprises a first thermistor disposed on the first surface and electrically coupled in series between the first port and the input line, a second thermistor disposed on the first surface and electrically coupled in series between the second port and the output line, and a first shunt resistor disposed on the first surface and coupled through the third port. The electronics package simultaneously achieves frequency equalization and temperature compensation for signals transmitted through the electronics package.

[0006] In another aspect of the invention, a method of manufacturing a frequency equalizer is provided that includes forming a coupler having a main segment extending between a first port and a second port and a coupling segment disposed in coupling relationship to the main segment and extending between a third port and a fourth port, electrically coupling a first thermistor in series between the first port and the input line, electrically coupling a second thermistor in series between the second port and the output line, and electrically coupling a first shunt resistor through the third port, wherein the frequency equalizer simultaneously achieves frequency equalization and temperature compensation for signals transmitted through the frequency equalizer. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating a representative frequency equalizer of the present invention. [Diagram 2] FIG. 2 is a plan view showing a representative electronic circuit package that can be a specific example of the frequency equalizer shown in FIG. [Diagram 3] FIG. 3 is a plan view showing another representative electronic circuit package which can be a specific example of the frequency equalizer shown in FIG. [Figure 4] FIG. 4 is a plan view showing yet another representative electronic circuit package which can be a specific example of the frequency equalizer shown in FIG. [Diagram 5] FIG. 5 is a flow chart illustrating an exemplary method for fabricating the frequency equalizer shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] As used throughout this specification and claims, approximating terms are intended to modify any quantitative expression to the extent that such modifications are permissible without changing the basic function to which it pertains. Thus, values ​​modified by terms such as "about," "approximately," and "substantially" should not be limited to the exact values ​​specified. In at least some instances, approximating terms may correspond to the precision of an instrument for measuring the value. In this case, and throughout this specification and claims, the limits of several numerical ranges may be combined or interchanged to identify such numerical ranges or to include subranges within such numerical ranges, unless the context or terminology indicates otherwise.

[0009] The presently disclosed systems and methods facilitate the combination of frequency equalization and temperature compensation for radio frequency (RF) applications using a single frequency equalizer circuit. The frequency equalizer circuit performs both frequency equalization and temperature compensation using a combination of couplers and thermistors. Thus, the presently disclosed frequency equalizer may improve frequency equalization and temperature compensation in RF applications while reducing the amount of material and physical space required to perform the frequency equalization and temperature compensation.

[0010] The patent subject matter disclosed herein includes a frequency equalizer having a coupler having a main segment extending between a first port and a second port and a coupling segment disposed in coupling relationship to the main segment and extending between a third port and a fourth port. The frequency equalizer further includes a first thermistor electrically coupled in series between the first port and an input line, a second thermistor electrically coupled in series between the second port and an output line, and a first shunt resistor coupled through the third port. The frequency equalizer simultaneously achieves frequency equalization and temperature compensation for signals transmitted through the frequency equalizer.

[0011] In one embodiment, the frequency equalizer further comprises a second shunt resistor coupled through the fourth port.

[0012] In some embodiments, the main segment and the join segment have different widths.

[0013] In one embodiment, the coupler further includes a second coupled segment disposed in a second coupled relationship with respect to the main segment and extending between the fifth port and the sixth port, and the frequency equalizer further includes a third shunt resistor electrically coupled through the fifth port and a fourth shunt resistor electrically coupled through the sixth port.

[0014] In one embodiment, the coupler further comprises a shunt line extending between the main segment and the mating segment.

[0015] In one embodiment, the length of the main segment is made greater than a quarter wavelength of the input signal to the frequency equalizer.

[0016] In one embodiment, the frequency equalizer further comprises a first inductor electrically coupled in parallel to the first thermistor and a second inductor electrically coupled in parallel to the second thermistor.

[0017] In an embodiment, at least one of the first thermistor and the second thermistor comprises a thermistor paste.

[0018] In one embodiment, the frequency equalizer further comprises at least one impedance-matching structure electrically coupled through at least one of the input line, the output line, the first port, and the second port.

[0019] 1, there is shown a frequency equalizer 100. The frequency equalizer 100 includes a coupler 102, a first thermistor 104, a second thermistor 106, a first shunt resistor 108, a second shunt resistor 110, a first inductor 112, and a second inductor 114.

[0020] The coupler 102 includes a main segment 116 and a coupling segment 118. The main segment 116 is a transmission line segment that extends between a first port 120 and a second port 122. The coupling segment 118 is a transmission line segment that extends between a third port 124 and a fourth port 126. In one embodiment, the main segment 116 and the coupling segment 118 are implemented as microstrip, stripline, and / or other types of RF transmission lines. The third port 124 is terminated with a first shunt resistor 108, and the fourth port 126 is terminated with a second shunt resistor 110. In one embodiment, the first shunt resistor 108 and the second shunt resistor 110 have resistance values ​​selected to provide a matched impedance load for the coupling segment 118. For example, in one embodiment, the first shunt resistor 108 and the second shunt resistor 110 each have a resistance value of 50 ohms.

[0021] The coupling segment 118 is disposed in a coupled relationship to the main segment 116. When RF power is received at the first port 120, it is transmitted through the second port 122 and the fourth port 126. The amount of power transmitted through one of the second port 122 and the fourth port 126 depends on the frequency of the RF power received at the first port 120. For example, if an input signal has a frequency corresponding to the main segment 116, which is a quarter wavelength (sometimes referred to as the "center frequency" in this case), a maximum amount of RF power can be transferred to the coupling segment 118 and transmitted through the fourth port 126, and a minimum amount of RF power can be transmitted through the second port 122. As the frequency of the input signal increases above the center frequency, an increasing amount of RF power is transmitted through the second port 122. Thus, when the coupler 102 operates over a range greater than the center frequency, it acts as an attenuator whose attenuation is inversely proportional to the input frequency, and the coupling segment 118 compensates for the tendency of RF signals to become more attenuated as they increase in frequency.

[0022] In one embodiment, the main segment 116 and the coupling segment 118 have certain transmission line characteristics (e.g., characteristic impedance, electrical length, distance between the transmission lines, etc.) selected to achieve a particular relationship between frequency and attenuation. For example, in one embodiment, the main segment 116 and the coupling segment 118 are microstrip lines, each having a different width and / or shape selected to achieve a particular coupling relationship.

[0023] The first thermistor 104 is electrically coupled between the first port 120 of the coupler 102 and an input 128, and the second thermistor 106 is electrically coupled between the second port 122 of the coupler 102 and an output 130. In one embodiment, the input 128 and the output 130 are, for example, an input transmission line and an output transmission line, respectively, where the frequency equalizer 100 receives an input signal at the input 128 and transmits an output signal at the output 130. The first thermistor 104 and the second thermistor 106 have resistance values ​​that change in response to a change in temperature of the first thermistor 104 or the second thermistor 106. For example, in one embodiment, the first thermistor 104 and the second thermistor 106 are negative temperature coefficient (NTC) thermistors having resistance values ​​that decrease as temperature increases. Thus, the amount of attenuation of the input signal by the first thermistor 104 and the second thermistor 106 decreases as temperature increases, causing the frequency equalizer 100 to compensate for the tendency of RF signals to be more attenuated as temperature increases.

[0024] The first inductor 112 is electrically coupled in parallel to the first thermistor 104, and the second inductor 114 is electrically coupled in parallel to the second thermistor 106. The first inductor 112 and the second inductor 114 each have an impedance that ignores the parasitic capacitances of the first inductor 112 and the second inductor 114, respectively, at a predetermined operating frequency.

[0025] FIG. 2 is a plan view of an exemplary electronics package 200, which is an exemplary embodiment of the frequency equalizer 100 (shown in FIG. 1). The electronics package 200 includes a substrate 202. The electronics package 200 further includes a coupler 102, a first thermistor 104, a second thermistor 106, a first shunt resistor 108, a second shunt resistor 110, a first inductor 112, and a second inductor 114, which are implemented as microstrips on the front side of the substrate 202 and function generally as described with respect to FIG. 1. The electronics package 200 further includes impedance matching structures 204, which are also implemented as microstrips on the front side of the substrate 202. The electronics package 200 further includes a ground plane (not shown) on the back side of the substrate 202.

[0026] The electronic circuit package 200 includes conductive traces (e.g., microstrips) that define, for example, the main segment 116, the coupling segment 118, the first thermistor 104, the second thermistor 106, the first shunt resistor 108, the second shunt resistor 110, the first inductor 112, and the second inductor 114, along with a ground plane. In some embodiments, at least one of the first thermistor 104, the second thermistor 106, the first shunt resistor 108, and the second shunt resistor 110 includes a paste (e.g., a thermistor paste) disposed on the substrate 202. Additionally or alternatively, in some embodiments, at least one of the first thermistor 104, the second thermistor 106, the first shunt resistor 108, and the second shunt resistor 110 includes another type of resistive component (e.g., a surface mount (SMT) component).

[0027] The impedance matching structures 204 are coupled through the input 128, the output 130, the first port 120 and the second port 122. The impedance matching structures 204 include a microstrip disposed on the front side of the substrate 202 and a via 206 extending between and providing an electrical connection between the microstrip and a ground plane disposed on the back side of the substrate 202. In one embodiment, the impedance matching structures 204 have a length selected to, for example, ignore parasitic capacitance in the electrical circuit package 200 at a predetermined operating frequency.

[0028] 3 is a plan view of another exemplary electronics package 300, which is another exemplary embodiment of the frequency equalizer 100 (shown in FIG. 1). The electronics package 300 includes the coupler 102, the first thermistor 104, the second thermistor 106, the first shunt resistor 108, the second shunt resistor 110, the first inductor 112, the second inductor 114, the substrate 202, the impedance adjustment structure 204, and the via 206, which function generally as described with respect to FIGS. 1 and 2. The electronics package 300 further includes a second coupling segment 302, a third shunt resistor 304, and a fourth shunt resistor 306.

[0029] The second coupled segment 302 extends between a fifth port 308 and a sixth port 310. The fifth port 308 terminates at a third shunt resistor 304, and the sixth port 310 terminates at a fifth shunt resistor 306. The shunt resistors 304 and 306 are matched impedance loads for the second coupled segment 302. For example, in one embodiment, the third shunt resistor 304 and the fourth shunt resistor 306 each have a resistance of 50 ohms.

[0030] The second coupling segment 302 is disposed in a coupled relationship to the main segment 116. The second coupling segment 302 functions generally as described for coupling segment 118 (shown in FIG. 1 ) and acts in conjunction with coupling segment 118 to compensate for the tendency of RF signals to become more attenuated as they increase in frequency. The second coupling segment 302 also increases the degree of coupling (e.g., the transfer of RF power from the main segment 116). Thus, the electronics package 300 has a high degree of ability to achieve a particularly desired relationship between frequency and attenuation.

[0031] FIG. 4 is a plan view of another exemplary electronic circuit package 400. The electronic circuit package 400 is another exemplary embodiment of the frequency equalizer 100 (shown in FIG. 1). The electronic circuit package 400 includes a coupler 102, a first thermistor 104, a second thermistor 106, a first shunt resistor 108, a first inductor 112, a second inductor 114, a substrate 202, an impedance adjustment structure 204, a through hole 206, a second coupling segment 302, and a third shunt resistor 304, which function generally as described with respect to FIGS. 1-3. FIG. 4 further includes a first shunt line 402 and a second shunt line 404.

[0032] The first shunt line 402 is a microstrip line extending between the first port 120 and the second port 126, and the second shunt line 404 is a microstrip line extending between the first port 120 and the sixth port 310. The first shunt line 402 and the second shunt line 404 further increase the coupling (e.g., the transfer of RF power from the main segment 116). Thus, the electronics package 400 has a high degree of ability to achieve a particularly desired relationship between frequency and attenuation.

[0033] 5 is an exemplary method 500 for fabricating the frequency equalizer 100 (shown in FIG. 1). In an exemplary embodiment, the method 500 includes forming 502 a coupler (e.g., coupler 102) having a main segment (e.g., main segment 116) extending between a first port (e.g., first port 120) and a second port (e.g., second port 122) and a coupling segment (e.g., coupling segment 118) disposed in a coupled relationship with the main segment and extending between a third port (e.g., third port 124) and a fourth port (e.g., fourth port 126). The method 500 further includes coupling 504 a first thermistor (e.g., first thermistor 104) in electrical series between the first port and the input line. The method 500 further includes coupling 506 a second thermistor (e.g., second thermistor 106) in electrical series between the second port and the output line. The method 500 further includes step 508 of electrically coupling a first shunt resistor (e.g., first shunt resistor 108) through the third port such that the frequency equalizer 100 simultaneously achieves frequency equalization and temperature compensation for signals transmitted through the frequency equalizer 100.

[0034] Exemplary embodiments of the method and system of the present invention have been described above in detail. The method and system of the present invention are not limited to the particular embodiments disclosed herein, but rather the components of the system of the present invention and / or steps of the method of the present invention can be used independently and separately from other components and / or steps disclosed herein. Thus, the exemplary embodiments of the present invention can be implemented and used in connection with many other areas not specifically disclosed herein.

[0035] The technical advantages of the systems and methods of the present invention disclosed herein include at least one of: (a) achieving frequency equalization for attenuation in an RF device using a coupler having a length greater than a quarter wavelength of the input signal; (b) achieving temperature compensation for attenuation in an RF device using one or more thermistors; and (c) reducing the physical space size of frequency equalization and temperature compensation circuitry by incorporating the frequency equalization and temperature compensation into a single electronic circuit package.

[0036] Although specific features of various embodiments disclosed herein may be shown in some drawings and not in others, this is for convenience only, and in accordance with the principles of the present disclosure, any feature of a drawing may be referenced and / or claimed in combination with any feature of any other drawing.

[0037] This specification uses examples to disclose various embodiments, including the best mode, and to enable any person skilled in the art to practice the present disclosure, including making and using any device or system, and performing any method implemented. The patentable scope of the present disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples shall be deemed to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that have only insubstantial differences from the literal language of the claims.

Claims

1. a coupler having a main segment extending between the first port and the second port and a coupling segment disposed in coupling relationship with the main segment and extending between the third port and the fourth port; a first thermistor electrically coupled in series between the first port and an input line; a second thermistor electrically coupled in series between the second port and an output line; a first shunt resistor coupled through the third port; 4. A frequency equalizer comprising: a first input terminal for receiving a first signal from said first equalizer; and a second input terminal for receiving said first equalizer;

2. 2. The frequency equalizer of claim 1, further comprising a second shunt resistor coupled across the fourth port.

3. 2. The frequency equalizer of claim 1, wherein the main segments and the combining segments have different widths.

4. 2. The frequency equalizer of claim 1, wherein the coupler further comprises a second coupled segment disposed in a second coupled relationship with the main segment and extending between a fifth port and a sixth port, the frequency equalizer further comprising: a third shunt resistor electrically coupled through the fifth port; and a fourth shunt resistor electrically coupled through the sixth port; A frequency equalizer comprising:

5. 2. The frequency equalizer of claim 1, wherein said coupler further comprises a shunt line extending between said main segment and said coupling segment.

6. 2. The frequency equalizer of claim 1, wherein the length of said main segments is greater than a quarter wavelength of an input signal to said frequency equalizer.

7. 2. The frequency equalizer of claim 1, further comprising a first inductor electrically coupled in parallel to the first thermistor and a second inductor electrically coupled in parallel to the second thermistor.

8. 2. The frequency equalizer of claim 1, wherein at least one of the first thermistor and the second thermistor comprises a thermistor paste.

9. 2. The frequency equalizer of claim 1, further comprising at least one impedance-matching structure electrically coupled through at least one of the input line, the output line, the first port, and the second port.

10. a substrate having a first surface and a second surface; a ground plane disposed on the second surface; a coupler having a main segment defined by a coupling strip and the ground plane disposed on said first surface and extending between a first port and a second port, and a coupling segment defined by a coupling strip and the ground plane disposed on said second surface and disposed in coupling relationship to said main segment and extending between a third port and a fourth port; a first thermistor disposed on the first surface and electrically coupled in series between the first port and an input line; a second thermistor disposed on the first surface and electrically coupled in series between the second port and an output line; a first shunt resistor coupled through the third port; In an electronic circuit package comprising: An electronic circuit package which simultaneously achieves frequency equalization and temperature compensation for signals transmitted through the electronic circuit package.

11. 11. The electronic circuit package of claim 10, further comprising a second shunt resistor disposed on the first surface and electrically coupled through the fourth port.

12. 11. The electronic circuit package of claim 10, wherein said main strips and said connecting strips have different widths.

13. 11. The electronic circuit package of claim 10, wherein the coupler further comprises a second coupling segment defined by a second coupling strip disposed on the first surface and the ground plane, the second coupling segment disposed in a second coupling relationship with the main segment and extending between a fifth port and a sixth port, and the frequency equalizer further comprises: a third shunt resistor disposed on the first surface and electrically coupled through the fifth port; a fourth shunt resistor disposed on the first surface and electrically coupled through the sixth port; An electronic circuit package comprising:

14. 11. The electronics package of claim 10, wherein said coupler further comprises a shunt line extending between said main segment and said mating segment.

15. 11. The electronic circuit package of claim 10, wherein the length of said main segments is greater than a quarter wavelength for an input signal of said frequency equalizer.

16. 11. The electronic circuit package of claim 10, further comprising a first inductor electrically coupled in parallel to the first thermistor and a second inductor electrically coupled in parallel to the second thermistor.

17. 11. The electronic circuit package of claim 10, wherein at least one of the first thermistor and the second thermistor has a thermistor paste disposed on the first surface.

18. 11. The electronics package of claim 10, further comprising at least one impedance adjusting structure electrically coupled through at least one of said input line and said output line.

19. A method for manufacturing a frequency equalizer, the method comprising the steps of: forming a coupler comprising a main segment extending between the first port and the second port and a coupling segment disposed in coupling relationship with the main segment and extending between the third port and the fourth port; coupling a first thermistor electrically in series between the first port and an input line; coupling a second thermistor electrically in series between the second port and an output line; electrically coupling a first shunt resistor through the third port; wherein the frequency equalizer simultaneously achieves frequency equalization and temperature compensation for a signal transmitted through the frequency equalizer.

20. 20. The method of claim 19, further comprising electrically coupling a second shunt resistor through the fourth port.

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