Wide Bandwidth Resonant Circuit

Abstract

To provide a wide-bandwidth resonant circuit.SOLUTION: In an embodiment disclosed herein, the wide-bandwidth resonant circuit includes a positive resonant circuit coupled in parallel to a negative resonant circuit. The positive resonant circuit and the negative resonant circuit can be configured to collectively exhibit certain impedance characteristics across a wide bandwidth. As a result, it is possible to utilize the wide-bandwidth resonant circuit to support a variety of wide-bandwidth applications, e.g., in a wide-bandwidth signal filter circuit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] Related Applications This application claims the benefit of U.S. Provisional Patent Application No. 63 / 167,712, filed March 30, 2021, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The techniques of this disclosure relate generally to resonant circuits, and more particularly to inductor-capacitor (LC) resonant circuits. [Background technology]

[0003] Wireless devices are becoming increasingly common in today's society. The proliferation of these wireless devices is driven in part by the many features now enabled on such devices to support a variety of applications based on a variety of wireless technologies (e.g., wide-area, local-area, and short-range wireless technologies) and in a variety of frequency bands (e.g., licensed and unlicensed bands). Summary of the Invention [Problem to be solved by the invention]

[0004] The ever-increasing number of frequency bands and demands for higher performance pose extremely challenging filtering requirements. These requirements continue to drive up the complexity of wireless devices, while there is a constant need to reduce the footprint and improve the performance (e.g., bandwidth) of the signal filters based thereon. [Means for solving the problem]

[0005] Aspects disclosed in the detailed description include wide-bandwidth resonant circuits. In embodiments disclosed herein, the wide-bandwidth resonant circuit includes a positive resonant circuit coupled in parallel with a negative resonant circuit. The positive and negative resonant circuits can be configured to collectively exhibit specific impedance characteristics over a wide bandwidth. As a result, the wide-bandwidth resonant circuit can be utilized to support a variety of wide-bandwidth applications, such as in wide-bandwidth signal filter circuits.

[0006] In one embodiment, a wide-bandwidth resonant circuit is provided. The wide-bandwidth resonant circuit includes a first node and a second node. The wide-bandwidth resonant circuit also includes a positive resonant circuit coupled between the first node and the second node. The positive resonant circuit is configured to resonate at a resonant frequency to present a respective higher impedance between the first node and the second node below the resonant frequency. The wide-bandwidth resonant circuit also includes a negative resonant circuit coupled between the first node and the second node and in parallel with the positive resonant circuit. The negative resonant circuit is configured to resonate at the resonant frequency to present a respective lower impedance between the first node and the second node above the resonant frequency.

[0007] In another aspect, a wide-bandwidth signal filter circuit is provided. The wide-bandwidth signal filter circuit includes a wide-bandwidth resonant circuit. The wide-bandwidth resonant circuit includes a first node and a second node. The wide-bandwidth resonant circuit also includes a positive resonant circuit coupled between the first node and the second node. The positive resonant circuit is configured to resonate at a resonant frequency to present a respective higher impedance between the first node and the second node below the resonant frequency. The wide-bandwidth resonant circuit also includes a negative resonant circuit coupled between the first node and the second node and in parallel with the positive resonant circuit. The negative resonant circuit is configured to resonate at the resonant frequency to present a respective lower impedance between the first node and the second node above the resonant frequency. The wide-bandwidth signal filter circuit also includes a load circuit coupled between the first node and the second node.

[0008] Those skilled in the art will appreciate the scope of the present disclosure and appreciate additional aspects thereof after reading the following detailed description in conjunction with the accompanying drawings.

[0009] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate several aspects of the present disclosure and, together with the description, serve to explain the principles of the disclosure. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a schematic diagram of an exemplary equivalent resonant circuit including a positive resonant circuit coupled in parallel to a negative resonant circuit. [Figure 2A] FIG. 2 is a schematic diagram providing an exemplary illustration of how a negative resonant circuit in the equivalent resonant circuit of FIG. 1 can be implemented based on an inductor network. [Figure 2B] FIG. 2 is a schematic diagram providing an exemplary illustration of how a negative resonant circuit in the equivalent resonant circuit of FIG. 1 can be implemented based on an inductor network. [Figure 2C] FIG. 2 is a schematic diagram providing an exemplary illustration of how a negative resonant circuit in the equivalent resonant circuit of FIG. 1 can be implemented based on an inductor network. [Figure 3] FIG. 1 is a schematic diagram of an exemplary wide bandwidth resonant circuit configured in accordance with an embodiment of the present disclosure to exhibit a particular impedance characteristic. [Figure 4] 4 is a graph providing an exemplary illustration of the impedance characteristics exhibited by the wide bandwidth resonant circuit of FIG. 3 over a wide bandwidth. [Figure 5A] 4 is a schematic diagram of an exemplary wide-bandwidth signal filter circuit configured to operate as a wide-bandwidth band-stop filter based on the wide-bandwidth resonant circuit of FIG. 3. [Figure 5B] 4 is a schematic diagram of an exemplary wide-bandwidth signal filter circuit configured to operate as a wide-bandwidth band-pass filter based on the wide-bandwidth resonant circuit of FIG. 3. [Figure 6]FIG. 10 is a schematic diagram of an exemplary wide bandwidth resonant circuit configured in accordance with an alternative embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] The embodiments described below represent the information necessary to enable those skilled in the art to practice the embodiments and illustrate the best modes for practicing the embodiments. Upon reading the following description in light of the accompanying drawings, those skilled in the art will understand the concepts of the present disclosure and will recognize applications of these concepts not specifically addressed herein. It is understood that these concepts and applications are within the scope of this disclosure and the appended claims.

[0012] Although terms such as "first," "second," etc. may be used herein to describe various elements, it will be understood that these elements are not limited by these terms. These terms are used only to distinguish one element from another. For example, a first element can be referred to as a second element, and similarly, a second element can be referred to as a first element, without departing from the scope of the present disclosure. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0013] When an element, such as a layer, region, or substrate, is referred to as being "on" or extending "onto" another element, it will be understood that it can be directly on or extending directly onto the other element, or that intervening elements may be present. In contrast, when an element is referred to as being "directly on" or extending "directly onto" another element, there are no intervening elements. Similarly, when an element, such as a layer, region, or substrate, is referred to as being "over" or extending "over" another element, it will be understood that it can be directly on or extending directly onto the other element, or that intervening elements may be present. In contrast, when an element is referred to as being "directly over" or extending "directly over" another element, there are no intervening elements. It will also be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.

[0014] Relative terms such as "lower" or "upper" or "upper" or "lower" or "horizontal" or "vertical" may be used herein to describe the relationship of one element, layer, or region to another element, layer, or region, as illustrated in the figures. It will be understood that these terms, and those discussed above, are intended to encompass various orientations of the device in addition to the orientation depicted in the figures.

[0015] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It will be further understood that as used herein, the terms "comprises," "comprising," "includes," and / or "including" specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0016] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein are to be interpreted as having a meaning consistent with their meaning in the context of the present specification and related art, and are not to be interpreted in an idealized or overly formal sense unless expressly defined as such herein.

[0017] Aspects disclosed in the detailed description include wide-bandwidth resonant circuits. In embodiments disclosed herein, the wide-bandwidth resonant circuit includes a positive resonant circuit coupled in parallel with a negative resonant circuit. The positive and negative resonant circuits can be configured to collectively exhibit specific impedance characteristics over a wide bandwidth. As a result, the wide-bandwidth resonant circuit can be utilized to support a variety of wide-bandwidth applications, such as in wide-bandwidth signal filter circuits.

[0018] FIG. 1 is a schematic diagram of an exemplary equivalent resonant circuit 10 including a positive resonant circuit 12 coupled in parallel to a negative resonant circuit 14 between a first node 16 and a second node 18. In a non-limiting example, the positive resonant circuit 12 and the negative resonant circuit 14 are each inductor-capacitor (LC) resonant circuits. More specifically, the positive resonant circuit 12 includes a positive capacitor C1 (having a positive capacitance C1) coupled in series with a positive inductor L1 (positive inductance L1). The negative resonant circuit 14 includes a negative capacitor C1 (having a negative capacitance C1) coupled in series with a negative inductor L1 (negative inductance L1). As discussed in detail below, the equivalent resonant circuit 10 can exhibit specific impedance characteristics over a wide bandwidth, thereby enabling the equivalent resonant circuit 10 to be employed in a variety of wideband applications, including, but not limited to, wideband signal filters, impedance inverters, and the like.

[0019] However, it may be difficult to provide a negative capacitance-C1 having a negative capacitance-C1 and a negative inductor-L1 having a negative inductance-L1 in a real circuit. Therefore, it is necessary to explore alternative ways to provide the negative capacitance-C1 and the negative inductance-L1 in the negative resonant circuit 14. As discussed in Figures 2A-2C, it is possible to provide the negative capacitance-C1 and the negative inductance-L1 in the negative resonant circuit 14 based on an inductor network.

[0020] Figure 2A is a schematic diagram of an inductor network 20 that may be utilized to provide a negative capacitance -C1 and a negative inductance -L1 to the equivalent resonant circuit 10 of Figure 1. Common elements between Figures 1 and 2A are shown therein with common element numbers and will not be described again herein.

[0021] In a non-limiting example, the inductor network 20 includes a first inductor 22, a second inductor 24, and an adjustable capacitor 26. The first inductor 22 is coupled between the first node 16 and the central node 28. The second inductor 24 is coupled between the central node 28 and the second node 18. The adjustable capacitor 26 is coupled between the central node 28 and ground (GND). Each of the first inductor 22 and the second inductor 24 has an inductance L and provides an overall mutual inductance M based on a coupling coefficient K (0 < K < 1). The adjustable capacitor 26 can be adjusted to provide a capacitance C0.

[0022] FIG. 2B shows an equivalent electrical network 30 of the inductor network 20 of FIG. 2A. Common elements between FIGS. 2A and 2B are shown therein with common element numbers and are not re-described herein.

[0023] In the equivalent electrical network 30, each of the first inductor 22 and the second inductor 24 can have an inductance L*(1 + K). The equivalent electrical network 30 further includes a third inductor 32 coupled between the central node 28 and the adjustable capacitor 26. The third inductor 32 has an inductance equal to -L*K.

[0024] The equivalent electrical network 30 can be converted from a T-network to a π-network presenting a negative capacitor equivalent to the negative capacitor -C1 and a negative inductor equivalent to the negative inductor -L1 of the equivalent resonant circuit 10 of FIG. 1. In this regard, FIG. 2C is a schematic diagram of an exemplary π-network 34 presenting an equivalent negative capacitor C NEG and an equivalent negative inductor L NEG The common elements between FIGS. 2B and 2C are shown therein with common element numbers and are not re-described herein.

[0025] As shown in FIG. 2C, the equivalent negative capacitor CNEG (Equivalent negative capacitance C NEG ) is connected between nodes N1 and N2 by an equivalent negative inductor L NEG (Equivalent negative inductance L NEG The π network 34 also includes an equivalent positive capacitor C between nodes N1 and N3 and between nodes N2 and N3. POS An equivalent positive inductor L coupled in series with POS The equivalent positive inductor L POS has an inductance of L(1-K) and an equivalent positive capacitor C POS has a capacitance of 1 / 2C0.

[0026] The π-type network 34 is connected at an operating frequency f oper The equivalent negative capacitance C NEG and the equivalent negative inductance L NEG In a non-limiting example, the operating frequency f oper , equivalent negative capacitance C NEG , and the equivalent negative inductance L NEG can be approximated according to the following equations (Equations 1.1, 1.2, and 1.3):

[0027]

number

number

number

[0028] The π-type network 34 operates at an operating frequency f oper The equivalent negative capacitance C NEG , and the equivalent negative inductance L NEG, it follows that the inductor network 20 of FIG. 2A can be used to provide the equivalent resonant circuit 10 of FIG. 1 with a negative capacitor -C1 having a negative capacitance -C1 and a negative inductor -L1 having a negative inductance -L1.

[0029] Figure 3 is a schematic diagram of an exemplary wideband resonant circuit 36 including a positive resonant circuit 38 configured according to the positive resonant circuit 12 of Figure 1 and a negative resonant circuit 40 configured according to the inductor network 20 of Figure 2A. Elements common between Figures 1, 2A, and 3 are indicated therein with common element numbers and will not be described again herein.

[0030] As shown in equations (Equations 1.2 and 1.3), the equivalent negative capacitance C NEG and the absolute value of the equivalent negative inductance L NEG It is possible to adjust the negative resonant circuit 40 based on L, C0 and / or K so that the absolute values of |C NEG |=C1 and |L NEG |=L1). Therefore, the positive resonant circuit 38 and the negative resonant circuit 40 both have a resonant frequency f RES to exhibit specific impedance characteristics over a wide bandwidth. As a result, the wide bandwidth resonant circuit 36 can be utilized for a variety of wide bandwidth applications in wide bandwidth signal filter circuits, impedance inverters, and the like.

[0031] Figure 4 is a graphical diagram providing an exemplary illustration of the impedance characteristics exhibited by the wide bandwidth resonant circuit 36 of Figure 3 over a wide bandwidth BW. The graphical diagram shown in Figure 4 includes a first impedance curve 42, a second impedance curve 44, a third impedance curve 46, and a fourth impedance curve 48.

[0032] A first impedance curve 42 illustrates the impedance characteristic exhibited by the positive resonant circuit 38 of Figure 3. As shown, the positive resonant circuit 38 has a resonant frequency f RES It resonates at a resonance frequency of f RES lower impedance Z PL and the resonant frequency f RES Higher impedance Z PH Present the following.

[0033] A second impedance curve 44 illustrates the impedance characteristics exhibited by the negative resonant circuit 40 of Figure 3. As shown, the negative resonant circuit 40 has a resonant frequency f RES It resonates at a resonance frequency of f RES at lower frequencies and with higher impedance Z NH and the resonant frequency f RES At higher frequencies, the impedance Z NL As previously discussed in FIGS. 2A-2C, inductor network 20 exhibits a resonant frequency f RES Operating frequency f lower than oper The equivalent negative capacitance C NEG and the equivalent negative inductance L NEG Therefore, the negative resonant circuit 40 can provide only the operating frequency f oper and the resonant frequency f RES The higher impedance Z NH Only the above items may be submitted.

[0034] The third impedance curve 46 shows the overall effect of the cancelling impedance characteristics between the positive resonant circuit 38 and the negative resonant circuit 40 over a wide bandwidth BW.

[0035] The fourth impedance curve 48 illustrates the overall filtering performance of the wideband resonant circuit 36 of Figure 3 over a wide bandwidth BW. Specifically, the wideband resonant circuit 36 has an operating frequency f oper Passes signals lower than the operating frequency f operTherefore, the wide bandwidth resonant circuit 36 can be used to provide a bandpass or bandstop signal filter.

[0036] Figure 5A is a schematic diagram of an exemplary wideband signal filter circuit 50 configured to operate as a wideband band-stop filter based on the wideband resonant circuit 36 of Figure 3. Common elements between Figures 3 and 5A are indicated therein with common element numbers and will not be described again herein.

[0037] The wide-bandwidth signal filter circuit 50 includes a load circuit 52 coupled in series with the wide-bandwidth resonant circuit 36 between the first node 16 and the second node 18. In accordance with the previous discussion of FIG. 4, the wide-bandwidth signal filter circuit 50 has an operating frequency f oper It can function as a wideband band-stop signal filter for blocking signals over a wide bandwidth BW above the

[0038] Figure 5B is a schematic diagram of an exemplary wide-bandwidth signal filter circuit 54 configured to operate as a wide-bandwidth band-pass filter based on the wide-bandwidth resonant circuit 36 of Figure 3. Common elements between Figures 3 and 5B are indicated therein with common element numbers and will not be described again herein.

[0039] The wideband signal filter circuit 54 includes a load circuit 56 coupled in parallel to the wideband resonant circuit 36 between the first node 16 and the second node 18. In accordance with the previous discussion of FIG. 4, the wideband signal filter circuit 54 has an operating frequency f oper It can function as a wideband bandpass signal filter to prevent signals from being shunted to ground over a wide bandwidth BW above 100 kHz.

[0040] The wide-bandwidth resonant circuit 36 of Figure 3 can be adapted to operate at two or more wide bandwidths. In this regard, Figure 6 is a schematic diagram of an exemplary wide-bandwidth resonant circuit 58 configured in accordance with an alternative embodiment of the present disclosure. Common elements between Figures 3 and 6 are indicated therein with common element numbers and will not be described again herein.

[0041] The wide bandwidth resonant circuit 58 includes a second wide bandwidth resonant circuit 60 coupled in series with the wide bandwidth resonant circuit 36. The second wide bandwidth resonant circuit 60 is coupled to the second node 18. a third node 62 coupled to 4th Node 64 and, In a non-limiting example, the third node 62 may be coupled to a coupling impedance Z COUP to the second node 18 via a coupling circuit 66 having

[0042] The second wideband resonant circuit 60 includes a second positive resonant circuit 38' and a second negative resonant circuit 40'. The second positive resonant circuit 38' is coupled between a third node 62 and a fourth node 64. The second positive resonant circuit 38' has a second resonant frequency f' RES It resonates at a second resonant frequency f' RES The second negative resonant circuit 40' is configured to present a respective lower impedance between the third node 62 and the fourth node 64 at a frequency lower than the second resonant frequency f'. The second negative resonant circuit 40' is coupled between the third node 62 and the fourth node 64 and in parallel with the second positive resonant circuit 38'. The second negative resonant circuit 40' is configured to present a respective lower impedance between the third node 62 and the fourth node 64 at a frequency lower than the second resonant frequency f'. RES It resonates at a second resonant frequency f' RES The third and fourth nodes 62, 64 are configured to present respective lower impedances between them at frequencies above 100 MHz.

[0043] Like the wide bandwidth resonant circuit 36, the second wide bandwidth resonant circuit 60 is configured to utilize the positive resonant circuit 12 of Figure 1 as the second positive resonant circuit 38' and the inductor network 20 of Figure 2A as the second negative resonant circuit 40'. Thus, the second wide bandwidth resonant circuit 60 is configured to operate based on the same principles as the wide bandwidth resonant circuit 36.

[0044] However, as can be appreciated, the L, C0, and K of the second wide bandwidth resonant circuit 60 can be determined independently of the L, C0, and K of the wide bandwidth resonant circuit 36. In this regard, the second resonant frequency f' of the second wide bandwidth resonant circuit 60 can be determined independently of the L, C0, and K of the wide bandwidth resonant circuit 36. RES is the resonant frequency f of the wideband resonant circuit 36 RES It may be different from or the same as.

[0045] Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure, and all such improvements and modifications are considered within the scope of the concepts disclosed herein and the following claims.

Claims

1. A wide bandwidth resonant circuit, comprising: a first node and a second node; a positive resonant circuit; a negative resonant circuit; the positive resonant circuit is coupled between the first node and the second node, the positive resonant circuit configured to resonate at a resonant frequency and present a first low impedance between the first node and the second node below the resonant frequency; The negative resonant circuit is a first inductor and a second inductor coupled in series between the first node and the second node and coupled in parallel to the positive resonant circuit; a tunable capacitor coupled between a central node located between the first inductor and the second inductor and ground; a wide bandwidth resonant circuit configured to resonate at the resonant frequency and present a second low impedance between the first node and the second node above the resonant frequency;

2. the positive resonant circuit is further configured to resonate at the resonant frequency and present a first high impedance between the first node and the second node above the resonant frequency, the first high impedance being higher than the first low impedance; 2. The wide bandwidth resonant circuit of claim 1, wherein the negative resonant circuit is further configured to resonate at the resonant frequency to present a second high impedance between the first node and the second node below the resonant frequency, the second high impedance being higher than the second low impedance.

3. the positive resonant circuit is further configured to exhibit a positive capacitance in series with a positive inductance between the first node and the second node; 3. The wide bandwidth resonant circuit of claim 2, wherein the negative resonant circuit is further configured to present an equivalent negative capacitance in series with an equivalent negative inductance between the first node and the second node.

4. the absolute value of the equivalent negative capacitance is equal to the positive capacitance; 4. The wide bandwidth resonant circuit of claim 3, wherein the absolute value of said equivalent negative inductance is equal to said positive inductance.

5. 4. The wide bandwidth resonant circuit of claim 3, wherein the positive resonant circuit comprises a capacitor having the positive capacitance coupled in series with an inductor having the positive inductance.

6. 4. The wide bandwidth resonant circuit of claim 3, wherein the negative resonant circuit is further configured to present the equivalent negative capacitance in series with the equivalent negative inductance between the first node and the second node above an operating frequency.

7. the operating frequency is lower than the resonant frequency; 7. The wide bandwidth resonant circuit of claim 6, wherein the negative resonant circuit is further configured to present the second high impedance below the resonant frequency and above the operating frequency.

8. A wide-bandwidth resonant circuit as described in claim 6, wherein the first inductor, the second inductor, and the adjustable capacitor are configured as a whole to present the equivalent negative capacitance in series with the equivalent negative inductance between the first node and the second node.

9. The operating frequency is [Equation 1] is approximated as The equivalent negative capacitance is: [Equation 2] is approximated as The equivalent negative inductance is: [Equation 3] is approximated as During the ceremony, L represents the inductance of each of the first inductor and the second inductor; K represents a coupling coefficient between the first inductor and the second inductor; C ０ 9. The wide bandwidth resonant circuit of claim 8, wherein: represents the capacitance of each of the adjustable capacitors.

10. 1. A wide bandwidth signal filter circuit, comprising: the wide-bandwidth signal filter circuit comprises a wide-bandwidth resonant circuit and a load circuit; The wide bandwidth resonant circuit comprises: a first node and a second node; a positive resonant circuit; a negative resonant circuit; the positive resonant circuit is coupled between the first node and the second node, the positive resonant circuit configured to resonate at a resonant frequency and present a first low impedance between the first node and the second node below the resonant frequency; The negative resonant circuit is a first inductor and a second inductor coupled in series between the first node and the second node and coupled in parallel to the positive resonant circuit; a tunable capacitor coupled between a central node located between the first inductor and the second inductor and ground; the negative resonant circuit is configured to resonate at the resonant frequency and present a second low impedance between the first node and the second node at a frequency higher than the resonant frequency; The wide bandwidth signal filter circuit, wherein the load circuit is coupled between the first node and the second node.

11. further comprising a second wideband resonant circuit coupled in series with the wideband resonant circuit, the second wideband resonant circuit comprising: a third node coupled to the second node; and a fourth node. a second positive resonant circuit coupled between the third node and the fourth node, the second positive resonant circuit configured to resonate at a second resonant frequency to present the first low impedance between the third node and the fourth node below the second resonant frequency; and a second negative resonant circuit coupled between the third node and the fourth node and in parallel with the second positive resonant circuit, the second negative resonant circuit configured to resonate at the second resonant frequency to present the second low impedance between the third node and the fourth node above the second resonant frequency.

12. 11. The wide-bandwidth signal filter circuit of claim 10, wherein the load circuit is coupled in series with the wide-bandwidth resonant circuit between the first node and the second node.

13. 11. The wide-bandwidth signal filter circuit of claim 10, wherein the load circuit is coupled in parallel with the wide-bandwidth resonant circuit between the first node and the second node.

14. the positive resonant circuit is further configured to resonate at the resonant frequency and present a first high impedance between the first node and the second node above the resonant frequency, the first high impedance being higher than the first low impedance; 11. The wide bandwidth signal filter circuit of claim 10, wherein the negative resonant circuit is further configured to resonate at the resonant frequency to present a second high impedance between the first node and the second node below the resonant frequency, the second high impedance being higher than the second low impedance.

15. the positive resonant circuit is further configured to exhibit a positive capacitance in series with a positive inductance between the first node and the second node; 15. The wide bandwidth signal filter circuit of claim 14, wherein the negative resonant circuit is further configured to present an equivalent negative capacitance in series with an equivalent negative inductance between the first node and the second node.

16. the absolute value of the equivalent negative capacitance is equal to the positive capacitance; 16. The wide bandwidth signal filter circuit of claim 15, wherein the absolute value of the equivalent negative inductance is equal to the positive inductance.

17. 16. The wide-bandwidth signal filter circuit of claim 15, wherein the positive resonant circuit comprises a capacitor having the positive capacitance coupled in series with an inductor having the positive inductance.

18. 16. The wide bandwidth signal filter circuit of claim 15, wherein the negative resonant circuit is further configured to present the equivalent negative capacitance in series with the equivalent negative inductance between the first node and the second node above an operating frequency.

19. the operating frequency is lower than the resonant frequency; 20. The wide bandwidth signal filter circuit of claim 18, wherein the negative resonant circuit is further configured to present the second high impedance below the resonant frequency and above the operating frequency.

20. The negative resonant circuit is the first inductor coupled between the first node and the central node; the second inductor coupled between the central node and the second node; the adjustable capacitor coupled between the central node and ground; 16. The wide bandwidth signal filter circuit of claim 15, wherein the first inductor, the second inductor, and the adjustable capacitor are configured to collectively present the equivalent negative capacitance in series with the equivalent negative inductance between the first node and the second node.

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