Systems and methods for coupled resonator filtering

Abstract

The coupled resonator filter (2604) includes a first parallel resonator including a first capacitance (C1) connected in parallel with a first inductance (L1), a second parallel resonator including a second capacitance (C2) connected in parallel with a second inductance (L2), and a third parallel resonator including a third capacitance (C3) connected in parallel with a third inductance (L3). Magnetic coupling occurs between the first inductance and the second inductance, between the second inductance and the third inductance, and between the first inductance and the third inductance according to first, second, and third coupling coefficients (k12, k23, k13), respectively. The frequency response of the coupled resonator filter includes a notch when the values ​​of the first coupling coefficient, the second coupling coefficient, and the third coupling coefficient satisfy predetermined conditions.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 63 / 402,882, entitled "SYSTEM AND METHOD FOR INTEGRATED FILTERING AND AMPLIFICATION," filed August 31, 2022.

[0002]

[0002] This application is related to Application No. ____ (Attorney Docket No. DOCK-031 / 02WO) entitled "INTEGRATED COUPLED RESONATOR FILTERING," filed on the same date as this application, and Application No. ____ (Attorney Docket No. DOCK-031 / 03WO) entitled "SYSTEM AND METHOD FOR INTEGRATED FILTERING AND AMPLIFICATION," filed on the same date as this application.

[0003] Field

[0003] The present disclosure relates generally to filter circuits, and more particularly to coupled resonator filters. [Background technology]

[0004] background Coupled resonator filters have been widely described in literature and scientific papers. See, for example, "The Design of Direct Coupled Band Pass Filters" (July 10, 2016), published by Iowa Hills Software, which has been used to calculate electrically coupled resonator filters. The majority of published documentation and literature on coupled resonator filters relates to cavity-based resonator filters. See, for example, the reference "Microwave Filters for Communication Systems" by Richard J. Cameron et al. Internet-based calculators are also available for calculating component parameters for capacitively coupled resonator filters. See, for example, the site https: / / rf-tools.com / lc-filter / . This particular online calculator is limited to calculating component parameters based on capacitive coupling and equal load and source impedances. Figure 1 is a screenshot of an exemplary user interface 100 generated by the coupled resonator filter calculator found at https: / / rf-tools.com / lc-filter / .

[0005]

[0005] Figure 2 provides an example of a source-gated feedback LNA topology 200 of the type described in the existing literature. See, for example, the paper "Analysis and Design of a Transformer-Feedback-based Wideband Receiver," IEEE Transactions on Microwave Theory and Technology, Vol. 61, No. 3, March 2013, Bhagavatula and Rudell. The output matching of the low noise amplifier (LNA) 210 of Figure 2 to a load is achieved by using an inductance 224 (L O ), capacitance 226(C match ) and resistor 228 (R O )(L O, which may include the inherent resistance associated with L and additional physical resistance, and an inductance 224 (L O ) and capacitance 226(C match ) is used for impedance transformation. The input impedance of the LNA in Figure 2 is defined by the characteristics of the active device 230 (M1) in combination with a feedback network consisting of a first inductance 240 (L1) coupled to a second inductance 242 (L2). Summary of the Invention [Means for solving the problem]

[0006] overview

[0006] Disclosed herein are innovative techniques for on-chip integrated RF filtering and amplification that can be utilized in high performance RF integrated circuits and front-end modules (FEMs) embedded in, for example, mobile phones, routers, and personal computers.

[0007] In one aspect, the present disclosure relates to a coupled resonator filter including a first parallel resonator, a second parallel resonator, and a third parallel resonator. The first parallel resonator includes a first capacitance connected in parallel with a first inductance. The second parallel resonator includes a second capacitance connected in parallel with a second inductance. The third parallel resonator includes a third capacitance connected in parallel with a third inductance. A magnetic coupling between the first inductance and the second inductance magnetically couples the first parallel resonator to the second parallel resonator according to a first coupling coefficient, a magnetic coupling between the second inductance and the third inductance magnetically couples the second parallel resonator to the third parallel resonator according to a second coupling coefficient, and a magnetic coupling between the first inductance and the third inductance magnetically couples the first parallel resonator to the third parallel resonator according to a third coupling coefficient. The frequency response of the coupled resonator filter includes a notch when the values ​​of the first coupling coefficient, the second coupling coefficient, and the third coupling coefficient satisfy a predetermined condition.

[0008]

[0008] The present disclosure also relates to an integrated circuit coupled resonator filter including a first parallel resonator, a second parallel resonator, and a third parallel resonator. The first parallel resonator includes a first capacitance connected in parallel with a first inductance. The second parallel resonator includes a second capacitance connected in parallel with a second inductance. The third parallel resonator includes a third capacitance connected in parallel with a third inductance. A magnetic coupling between the first inductance and the second inductance magnetically couples the first parallel resonator to the second parallel resonator according to a first coupling coefficient, a magnetic coupling between the second inductance and the third inductance magnetically couples the second parallel resonator to the third parallel resonator according to a second coupling coefficient, and a magnetic coupling between the first inductance and the third inductance magnetically couples the first parallel resonator to the third parallel resonator according to a third coupling coefficient. The frequency response of the coupled resonator filter includes a notch when the values ​​of the first coupling coefficient, the second coupling coefficient, and the third coupling coefficient satisfy a predetermined condition.

[0009]

[0009] The inductances of the coupled resonator filter may be implemented in various configurations and on various layers of an integrated circuit. For example, the first inductance, the second inductance, and the third inductance may be implemented on multiple layers of the integrated circuit and at least partially overlap. Alternatively, at least the first inductance and the second inductance may be implemented on the same layer of the integrated circuit and may not overlap. The third inductance may also be implemented on the same layer of the integrated circuit and may not overlap with the first inductance and the second inductance.

[0010] In another configuration, two of the first inductance, the second inductance, and the third inductance are implemented on a first layer of an integrated circuit, and the remaining one of the first inductance, the second inductance, and the third inductance is implemented on a second layer of the integrated circuit. In one implementation of this configuration, at least one of the two of the first inductance, the second inductance, and the third inductance implemented on the first layer of the integrated circuit overlaps with the remaining one of the first inductance, the second inductance, and the third inductance implemented on the second layer of the integrated circuit.

[0011]

[0011] The first inductance, the second inductance, and the third inductance may be implemented on different layers of an integrated circuit. In this case, the first inductance, the second inductance, and the third inductance may be arranged to at least partially overlap. Alternatively, two of the first inductance, the second inductance, and the third inductance may be arranged to at least partially overlap.

[0012] In another aspect, the present disclosure relates to an integrated circuit coupled resonator filter including a low-noise amplifier and a first parallel resonator, a second parallel resonator, and a third parallel resonator. The first parallel resonator includes a first capacitance connected in parallel with a first inductance. The second parallel resonator includes a second capacitance connected in parallel with the second inductance. The third parallel resonator includes a third capacitance connected in parallel with the third inductance, and the third parallel resonator is coupled to an input of the low-noise amplifier. The first coupling capacitance is connected between the first parallel resonator and the second parallel resonator. The coupling capacitance capacitively couples the first parallel resonator and the second parallel resonator. The second coupling capacitance is connected between the second parallel resonator and the third parallel resonator. The second coupling capacitance capacitively couples the second parallel resonator and the third parallel resonator. The magnetic coupling between the first inductance and the second inductance magnetically couples the first parallel resonator and the second parallel resonator according to a first coupling coefficient, the magnetic coupling between the second inductance and the third inductance magnetically couples the second parallel resonator and the third parallel resonator according to a second coupling coefficient, and the magnetic coupling between the first inductance and the third inductance magnetically couples the first parallel resonator and the third parallel resonator according to a third coupling coefficient. The frequency response of the coupled resonator filter includes a notch when the values ​​of the first coupling coefficient, the second coupling coefficient, and the third coupling coefficient satisfy a predetermined condition.

[0013] The present disclosure also relates to a low-noise amplifier and an integrated circuit coupled resonator filter including a first parallel resonator, a second parallel resonator, and a third parallel resonator. The first parallel resonator includes a first capacitance connected in parallel with a first inductance. The second parallel resonator includes a second capacitance connected in parallel with a second inductance. The third parallel resonator includes a third capacitance connected in parallel with a third inductance and is coupled to an input of the low-noise amplifier. A magnetic coupling between the first inductance and the second inductance magnetically couples the first parallel resonator to the second parallel resonator according to a first coupling coefficient, a magnetic coupling between the second inductance and the third inductance magnetically couples the second parallel resonator to the third parallel resonator according to a second coupling coefficient, and a magnetic coupling between the first inductance and the third inductance magnetically couples the first parallel resonator to the third parallel resonator according to a third coupling coefficient. The frequency response of the coupled resonator filter includes a notch when the values ​​of the first coupling coefficient, the second coupling coefficient, and the third coupling coefficient satisfy a predetermined condition.

[0014] In yet another aspect, the present disclosure relates to an integrated circuit coupled resonator filter, including a low-noise amplifier, an Nth-order coupled resonator filter, and an Mth-order coupled resonator filter. The Nth-order coupled resonator filter is coupled to an input of the low-noise amplifier and includes N magnetically coupled parallel resonators arranged in series, where N is at least 3, and the N magnetically coupled parallel resonators are configured to induce substantially only magnetic coupling between them. The Mth-order coupled resonator filter is coupled to an output of the low-noise amplifier and includes M magnetically coupled parallel resonators arranged in series, where M is at least 3, and the M magnetically coupled parallel resonators are configured to induce substantially only magnetic coupling between them.

[0015]

[0015] A first parallel resonator of the N parallel resonators may be connected to a signal source and configured with an input impedance equal to the impedance of the signal source, and an Mth parallel resonator of the M parallel resonators may be connected to a signal load and configured with an output impedance equal to the impedance of the signal load.

[0016] The frequency response of the N-th coupled resonator filter may include a first notch at a first frequency that depends on coupling characteristics between the parallel resonators of the N parallel resonators. The frequency response of the M-th coupled resonator filter may include a second notch at a second frequency that depends on coupling characteristics between the parallel resonators of the M parallel resonators.

[0017] The present disclosure is further directed to a programmable coupled resonator filter arrangement including an Nth-order coupled resonator filter. The Nth-order coupled resonator filter includes N magnetically coupled parallel resonators arranged in series, where N is at least 3. Each of the N magnetically coupled parallel resonators includes an inductance in parallel with a programmable capacitance arrangement. The frequency response of the coupled resonator filter arrangement includes a first notch at a first frequency that depends on coupling characteristics between the N parallel resonators.

[0018]

[0018] Each programmable capacitance arrangement may include a capacitance connected to a switch, each switch including a terminal connected to signal ground.

[0019] The programmable coupled resonator filter arrangement may further include a series resonant circuit connected in parallel with any of the N magnetically coupled parallel resonators, and the frequency response of the coupled resonator filter arrangement may include a second notch at a second frequency that depends on the resonant frequency of the series resonant circuit.

[0020] BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The features, nature and advantages of the present disclosure will become more apparent from the detailed description set forth below when considered in conjunction with the drawings in which like reference characters identify consistently throughout. [Brief explanation of the drawings]

[0021] [Figure 1] 10 is a screenshot of an exemplary user interface generated by an online coupled resonator filter calculator. [Figure 2]

[0022] 1 illustrates an exemplary topology of a source-gate feedback low noise amplifier (LNA). [Figure 3]

[0023] 1 illustrates an exemplary topology of a source-degenerated LNA. [Figure 4A]

[0024] FIG. 1 is a system block diagram of a receiver with filtering and amplification according to the present disclosure. [Figure 4B]

[0025] FIG. 1 is a system block diagram of a receiver operable to perform Q-boost filtering and amplification in accordance with the present disclosure. [Figure 4C]

[0026] FIG. 1 is a block diagram of an example implementation of a Q-boost band-stop filter. [Figure 5A]

[0027] FIG. 1 is an expanded system block diagram of a receiver with filtering and amplification according to the present disclosure. [Figure 5B]

[0028] FIG. 1 is an expanded system block diagram of a receiver operable to perform Q-boost filtering and amplification in accordance with the present disclosure. [Figure 6]

[0029] 1 illustrates a schematic diagram of a cubic coupled resonator filter having both magnetic and electric coupling according to the present disclosure. [Figure 7]

[0030] 1 illustrates a schematic diagram of a cubic coupled resonator filter with only magnetic coupling according to the present disclosure; [Figure 8]

[0031] 1 illustrates a schematic diagram of a quadratic coupled resonator filter having both magnetic and electric coupling according to the present disclosure. [Figure 9]

[0032] 1 illustrates a schematic diagram of a quadratic coupled resonator filter with only magnetic coupling according to the present disclosure; [Figure 10]

[0033] 1 is a screenshot of an electronic spreadsheet interface used to determine the component parameters of the filter. [Figure 11]

[0034] 1 illustrates an exemplary layout of inductors included in a third-order resonator filter with primarily electrical coupling. [Figure 12]

[0035] 1 illustrates an exemplary layout of inductors for a third-order resonator filter with combined electrical and magnetic coupling. [Figure 13]

[0036] 1 illustrates an exemplary layout of a third-order resonator filter with combined electrical and magnetic coupling. [Figure 14]

[0037] 1 illustrates an exemplary layout of a third-order resonator filter with only magnetic coupling. [Figure 15]

[0038] 1 illustrates an exemplary layout of a second-order resonator filter with only magnetic coupling. [Figure 16]

[0039] 1 illustrates an exemplary layout of inductors for a third-order resonator filter with only magnetic coupling. [Figure 17]

[0040] 1 illustrates an exemplary layout of inductors for a third-order resonator filter with only magnetic coupling. [Figure 18]

[0041] 1 illustrates an exemplary layout of a third-order resonator filter with only magnetic coupling. [Figure 19]

[0042] 19 illustrates the results of an electromagnetic simulation characterizing the coupling coefficient between inductors of the layout of FIG. 18. [Figure 20]

[0043] 1 illustrates a typical frequency response of a third-order resonator filter. [Figure 21]

[0044] 5C illustrates both the simulated and measured frequency responses of the receiver of FIG. 5B implemented with a third-order resonator filter configured to introduce a frequency response notch in accordance with the present disclosure. [Figure 22]

[0045] 1 illustrates a schematic diagram of a coupled resonator filter in combination with a source-degenerate LNA according to the present disclosure. [Figure 23]

[0046] 1 illustrates a schematic diagram of a coupled resonator filter with only magnetic coupling in combination with a source-degenerated LNA. [Figure 24]

[0047] 1 illustrates a schematic diagram of a coupled resonator filter with only magnetic coupling in combination with a source-gated feedback LNA. [Figure 25]

[0048] 10A and 10B illustrate schematically a coupled resonator filter with only magnetic coupling configured in combination with a source-gated feedback LNA to produce a frequency response with an input notch. [Figure 26]

[0049] 1 illustrates a schematic diagram of a coupled resonator filter in combination with a source-gate feedback LNA and an input notch circuit. [Figure 27]

[0050] 1 shows a schematic diagram of a coupled resonator filter with only magnetic coupling, which combines a source-gate feedback LNA, an input notch circuit and a coupled resonator filter with only magnetic coupling at the output. [Figure 28]

[0051] 10 illustrates the frequency response of a filter and an LNA implementation with and without an additional input notch. [Figure 29]

[0052] 1 illustrates the output return loss (S22) of a tunable filter in which a wideband response is achieved by a coupled resonator filter at the output. [Figure 30]

[0053] 5C illustrates the notched frequency response of the receiver of FIG. 5B implemented with a coupled resonator filter with only magnetic coupling, where the center frequency of the filter is programmable for two different frequency bands. [Figure 31]

[0054] 1 illustrates a schematic diagram of a CMOS implementation of a source-gate feedback LNA topology. [Figure 32A]

[0055] 1 illustrates an exemplary layout of an electrically coupled resonator filter and a source degenerate LNA. [Figure 32B]

[0056] 1 illustrates an exemplary layout of a magnetically coupled resonator filter and a source-degenerated LNA. [Figure 33]

[0057] 1 illustrates a schematic diagram of a CMOS implementation of a source-gate feedback LNA topology configured for distortion cancellation. [Figure 34]

[0058] FIG. 1 is a schematic diagram of a tunable coupled resonator filter. [Figure 35]

[0059] 35 illustrates the frequency response of the tunable coupled resonator filter of FIG. 34 when configured in two different filter modes. [Figure 36]

[0060] 35 illustrates an exemplary capacitor filter bank of the type that may be used to implement programmable capacitance in the filter of FIG. 34. DETAILED DESCRIPTION OF THE INVENTION

[0022] Detailed Description

[0061] Disclosed herein are innovative techniques for on-chip integrated RF filtering, noise and distortion suppression, and amplification that can be utilized in high-performance RF integrated circuits and front-end modules embedded within, for example, mobile phones, routers, and personal computers.

[0023]

[0062] The innovative technologies described in this disclosure can be broadly divided into two groups: (i) integrated magnetically and electrically coupled on-chip resonator filters, and (ii) on-chip coupled resonator filters combined with low-noise amplifiers (LNAs). Innovations within groups (i) and (ii) can function independently, but are also advantageous when combined. Details of the innovations within each group are described in the following sections.

[0024] Exemplary Receiver Architecture with Filtering and Amplification

[0063] 4A is a system block diagram of a receiver 400 with filtering and amplification according to the present disclosure. As shown in FIG. 4A, the receiver 400 includes a first Nth-order coupled resonator filter 410 and a second Nth-order coupled resonator filter 420, a low noise amplifier 430 connected to the output of the coupled resonator filter 410, and a variable attenuator 440 interposed between the LNA 430 and the coupled resonator filter 420. The first Nth-order coupled resonator filter 410 has a source resistor 436 (R S ) from a signal source 434 having a load 460 (R L ), the placement of a second Nth-order coupled resonator filter 420 at the output of the receiver 400 coupled to the first Nth-order coupled resonator filter 420 can provide a broader bandwidth output match than conventional single-resonator resonant loads and matching networks of the type shown in FIG. 3. While the example receiver 400 of FIG. 4A includes a first Nth-order coupled resonator filter and a second Nth-order coupled resonator filter implemented as described below, other receiver embodiments according to the present disclosure may include additional coupled resonator filters, attenuators, etc. In other receiver embodiments within the scope of the present disclosure, the number of coupled resonator filters and their orders (e.g., N=3, 4, etc.) and whether such filters are augmented with coupled-notch circuits will depend on the filtering requirements or specifications associated with a particular application.

[0025]

[0064] 4A, in one embodiment, the receiver 400 includes a bypass mode switch module 464. When the switch module 464 is in a closed configuration, the low noise amplifier 430 and the variable attenuator 440 are bypassed; otherwise, the signal energy from the resonator filter 410 is amplified by the LNA 430 and variably attenuated by the variable attenuator 440 before being provided to the second N-th order coupled resonator filter 420.

[0026]

[0065] Referring now to FIG. 4B , a system block diagram of a receiver 400′ operative to perform Q-boost filtering and amplification in accordance with the present disclosure is provided. As can be seen, the architecture of the receiver 400′ is substantially similar to that of the receiver 400. However, instead of a first N-th order coupled resonator filter 410 and a second N-th order coupled resonator filter 420, the receiver 400′ includes a first Q-boost coupled resonator filter module 412 and a second Q-boost coupled resonator filter module 422. As shown, the first Q-boost coupled resonator filter module 412 includes an N-th order coupled resonator filter 410′ and a coupled notch circuit 450′, which may be substantially similar or identical to the N-th order coupled resonator filter 410 and the coupled notch circuit 450 of FIG. 4A . In the first Q-boost coupled resonator filter module 412, the N-th order coupled resonator filter 410′ and the coupled notch circuit 450′ are connected to a regenerative feedback and Q-boost circuit 470. In one embodiment, the regenerative feedback and Q-boost circuit 470 includes an active device (e.g., a MOSFET) configured in a positive feedback loop. This arrangement allows the active device to create a negative transconductance, improving the quality factor (Q) of the inductive element coupled resonator filter 410′ and the coupled notch circuit 450′ by offsetting the parasitic losses inherent in the inductive element coupled resonator filter 410′ and the coupled notch circuit 450′. By boosting the Q of the coupled resonator filter 410′ and the coupled notch circuit 450′, it is possible to obtain very sharp attenuation at the edges of the filter bandpass generated jointly by the filters 410′, 450′.

[0027]

[0066] The second Q-boost coupled resonator filter module 422 includes an N-th order coupled resonator filter 420′, which may be substantially similar to or identical to the N-th order coupled resonator filter 420 of FIG. 4A. In addition, the second Q-boost coupled resonator filter module 422 includes a regenerative feedback and Q-boost circuit 480 connected to the N-th order coupled resonator filter 420′. The regenerative feedback and Q-boost circuit 480 may be configured similarly to the Q-boost circuit 470 to boost the Q of the coupled resonator filter 420′.

[0028]

[0067] Attention is now directed to FIG. 4C, which is a block diagram of an exemplary implementation of the regenerative feedback and Q-boost circuit 480 as a Q-boost band-stop filter 480′. As shown, the Q-boost band-stop filter 480′ is connected in parallel with the N-th order coupled resonator filter 420′ and coupled across a load 479 (R L ). The Nth-order coupled resonator filter 420′ is coupled to a source resistor 476 (R S 4C , the Q-boost band-stop filter 480′ includes a series resonant circuit 482 having a capacitance 486 and an inductance 488. A specially configured regenerative electronic circuit 490 in parallel with the capacitance 486 adds a negative resistance to the capacitance 486. By carefully selecting the parameters of the circuit 490, at least the losses in the inductance 488 are canceled by the added negative resistance, thereby increasing the Q factor of the series resonant circuit 482.

[0029]

[0068] Q-boost circuit 480, implemented as a Q-boost bandstop filter 480', offers many advantages over conventional methods for improving receiver performance. For example, improving the sharpness of a receiver's filter frequency response typically requires the use of higher-order filters or the addition of bulky and expensive acoustic filter elements. Furthermore, simply using conventional bandstop filters to improve the sharpness of the filter response at the filter band edges is generally not a feasible approach because, to the extent that such filters may improve the filter roll-off characteristics, their relatively low quality factor can degrade the shape of the filter passband and cause interference in adjacent bands.

[0030]

[0069] The Q-boosted bandstop filter 480' has a higher quality factor than conventional bandstop filters, thereby improving the filter's roll-off / clarity characteristics without degrading the filter's passband characteristics or interfering with adjacent frequency bands. To facilitate implementation of the Q-boosted bandstop filter 480' in integrated circuits, embodiments of the filter 480' are designed to overcome various challenges that have hindered the introduction of positive feedback amplifiers in integrated filter technology for Q-boosting purposes. For example, the dimensions of the circuit 490 are designed to eliminate oscillatory behavior while the overall resistive portion of the resonator 420' remains positive. The negative resistance introduced by the circuit 490 reduces the inductance losses of each resonator 410', 420', allowing it to be approximated by its parallel equivalent at resonance. At frequencies away from the resonant frequency, the reactive elements of the resonators 410', 420' dominate, and the negative resistance can be neglected. As a result, signals at out-of-band frequencies are generally unaffected.

[0031]

[0070] 5A, there is shown an expanded system block diagram of a receiver 500 with filtering and amplification according to the present disclosure. As shown in FIG. 5A, the receiver 500 includes an N-th order magnetically coupled resonator filter 510 connected in series with a band-stop filter 520, a low-noise amplifier 530 connected to the output of the band-stop filter 520, and a variable attenuator 540 interposed between the LNA 530 and an output matching network 550. The N-th order coupled resonator filter 510 and the coupled notch circuit 512 are coupled to a source resistor 504 (R S ) from a signal source 502. The receiver 500 includes an additional band-stop filter 560 and a load 574 (R L ) and an output low-pass filter 570 coupled to the coupled-resonator filter 510. A coupled-notch circuit 512 may be added to the coupled-resonator filter 510 to improve out-of-band attenuation in a manner similar to the coupled-notch filter 450 (FIG. 4). While the example receiver 500 of FIG. 5A includes only a single Nth-order coupled-resonator filter, other embodiments of receivers according to the present disclosure may include additional coupled-resonator filters, attenuators, etc.

[0032]

[0071] 5A , in one embodiment, receiver 500 includes a bypass mode switch module 578. When switch module 589 is in a closed configuration, low noise amplifier 530 and variable attenuator 540 are bypassed; otherwise, signal energy from band-stop filter 520 is amplified by LNA 530 and variably attenuated by variable attenuator 540 before being provided to output matching network 550. Receiver 500 may include a temperature-controlled bias module 582 for biasing active components of low noise amplifier 530 as a function of temperature, e.g., so that the gain of the low noise amplifier is substantially temperature independent.

[0033]

[0072] 5B, an expanded system block diagram of a receiver 500′ operable to perform Q-boost filtering and amplification in accordance with the present disclosure is provided. As can be seen, the architecture of receiver 500′ is substantially similar to that of receiver 500. However, instead of an N-th order coupled resonator filter 510, receiver 500′ includes a Q-boost coupled resonator filter module 508. As shown, Q-boost coupled resonator filter module 508 includes an N-th order coupled resonator filter 510′ and a coupled-notch circuit 512′, which may be substantially similar or identical to N-th order coupled resonator filter 510 and coupled-notch circuit 512 of FIG. 5A. As shown, in Q-boost coupled resonator filter module 508, N-th order coupled resonator filter 510′ and coupled-notch circuit 512′ are connected to a regenerative feedback and Q-boost circuit 514. In one embodiment, the regenerative feedback and Q-boost circuit 514 is implemented in essentially the same manner as the Q-boost band-stop filter 480′ of FIG. 4C. That is, the circuit 514 is implemented to include an active device (e.g., a MOSFET) configured in a positive feedback loop. With this arrangement, the active device creates a negative transconductance, improving the quality factor (Q) of the coupled resonator filter 510′ and the coupled notch circuit 512′ by offsetting the parasitic losses inherent in the inductive elements of the respective filters. By boosting the Q of the coupled resonator filter 510′ and the coupled notch circuit 512′, it is possible to obtain very sharp attenuation at the edges of the filter bandpass generated jointly by the filters 510′, 512′.

[0034] Integrated magnetoelectrically coupled resonator filters.

[0073] Attention is now directed to FIG. 6, which schematically illustrates a cubic coupled resonator filter 600 having both magnetic and electric coupling in accordance with the present disclosure. As shown, an input matching capacitance 608 (Cms_in) is connected in series with a signal source 610 having a source resistance 612 (RS). The three resonators of the cubic coupled resonator filter 600 each consist of a parallel combination of a first resonator 620 (L1 and C1), a second resonator 622 (L2 and C2), and a third resonator 624 (L3 and C3). The filter 600 also includes an output matching capacitance 630 (Cms_out) connected in series with a load represented by a load resistance 634 (RL).

[0035]

[0074] The electrical coupling between the first and second resonators of the resonator filter 600 is achieved by a first capacitance 640 (C12), and a second capacitance 644 (C23) provides electrical coupling between the second and third resonators. The amount of magnetic coupling between the first and second resonators is characterized by a coupling coefficient k12, and k23 indicates the amount of magnetic coupling between the second and third resonators. The direct magnetic coupling between the first and third resonators is characterized by k13. The coupling coefficient between two on-chip inductors is characterized by electromagnetic simulation and is defined by the following equation:

number

[0036]

[0075] While filter 600 could theoretically be implemented using any number of resonators, for purposes of on-chip integration, it is anticipated that using either two or three resonators will be the most practical approach. Mathematical formulas capable of calculating the parameters of filter 600 have been derived and entered into an electronic spreadsheet (e.g., an Excel sheet) for ease of calculation. These formulas are described in a separate section below.

[0037]

[0076] 10 illustrates a screenshot of an interface 1000 of an electronic spreadsheet used to determine the component parameters of a filter according to the present disclosure. In one implementation, the following procedure is employed to derive the component values ​​of filter 600 and other coupled resonator filters described herein using a spreadsheet. (1) Select the source and load impedance (2) Select the filter bandwidth and center frequency (3) Select the desired inductance value (4) Select the filter passband ripple (5) Select the desired amount of magnetic coupling (-100% to +100%)

[0038]

[0077] When values ​​associated with steps (1) through (5) of the procedure are entered into an electronic spreadsheet (e.g., in cells of interface 1000 having blue text, as shown in FIG. 10), all component values ​​are calculated based on the derived formulas described herein.

[0039]

[0078] It can be appreciated that implementing a filter with only electrical coupling places constraints on the implementation of filters realized as integrated circuits, since to avoid magnetic coupling between the inductors in the resonators, the inductors must be spaced far apart, which deviates from the intended filter performance. This spacing requires a layout that consumes a large amount of chip area, which is inconvenient. In contrast, the inventors have discovered that combining electrical and magnetic coupling provides multiple benefits, such as reduced chip area. Using only magnetic coupling further reduces the required chip area and eliminates wiring to the capacitances connecting different resonators. As a result, the layout is significantly easier to implement.

[0040]

[0079] 7, a schematic diagram of a cubic coupled resonator filter 700 having only magnetic coupling is provided. As with the cubic coupled resonator filter 600 of FIG. 6, the cubic coupled resonator filter 700 includes three resonators, each consisting of a parallel combination of a first resonator 720 (L1 and C1), a second resonator 722 (L2 and C2), and a third resonator 724 (L3 and C3). The filter 700 includes an output matching capacitance 730 (Cms_out) connected in series with a load represented by a load resistor 734 (RL).

[0041]

[0080] As shown, filter 700 does not have an input matching capacitance in series with the source impedance 712 (RS) of signal source 710 (input matching capacitance 608 present in filter 600 is not included in filter 700). This forces the impedance level of first resonator 720 (L1, C1) to be equal to source impedance 712 (RS) when proper input matching is achieved. Eliminating the first matching capacitance Cms_in in filter 700 is advantageous from an electrostatic discharge (ESD) perspective, as shunt inductor L1 protects the input from ESD pulses, thereby eliminating the need for dedicated ESD protection diodes. Such diodes can cause distortion when large signals are applied at the input of filter 700.

[0042]

[0081] 14 illustrates an example layout of a third-order resonator filter 1400 with only magnetic coupling. When using only magnetic coupling, as in filter 1400, inductors L1, L2, and L3 can be laid out on top of each other, which is beneficial from the perspective of saving chip area. As can be seen when using only magnetic coupling, the coupling capacitors are equal to zero, eliminating the need for wiring to the coupling capacitors (C12 and C23 in FIG. 6), simplifying the layout.

[0043]

[0082] FIG. 8 schematically illustrates a quadratic coupled resonator filter 800 having both magnetic and electrical coupling in accordance with the present disclosure. As shown, the filter 800 includes an input matching capacitance 808 (Cms_in) connected in series with a signal source 810 having a source resistance 812 (RS). The two resonators included within the filter 800 consist of a first resonator 820 and a second resonator 822 formed from parallel combinations of L1 and C1 and L2 and C2, respectively. Electrical coupling between the two resonators is achieved by capacitance 840 (C12), and the amount of magnetic coupling is characterized by a coupling coefficient k12. The filter 800 also includes an output matching capacitance 830 (Cms_out) connected in series with a load represented by a load resistance 834 (RL).

[0044]

[0083] FIG. 9 schematically illustrates a quadratic coupled resonator filter 900 with only magnetic coupling. The filter 900 includes an input matching capacitance 908 (Cms_in) connected in series with a signal source 910 having a source resistance 912 (RS). The two resonators included within the filter 900 consist of a first resonator 920 and a second resonator 922 formed from the parallel combinations of L1 and C1 and L2 and C2, respectively. As can be seen from FIG. 9, the filter does not include a coupling capacitor (i.e., the coupling capacitor C12 present in the filter 800 of FIG. 8 has been removed), and the frequency response of the filter 900 is achieved solely through magnetic coupling. The filter 900 also includes an output matching capacitance 930 (Cms_out) connected in series with a load represented by a load resistance 934 (RL).

[0045]

[0084] Attention is now directed to FIGS. 11-18, which provide examples of various inductor layouts that can be utilized to implement the coupled resonator filters of the present disclosure. As will be appreciated, there are numerous ways to implement an inductor layout that results in a desired coupling coefficient between the resonators of the coupled resonator filters of the present disclosure. By way of example only, FIG. 11 illustrates an exemplary layout of inductors included in a third-order resonator filter 1100 having primarily electrical coupling. As shown, a first inductor 1110 (L1) is included within the first resonator, a second inductor 1120 (L2) is included within the second resonator, and a third inductor 1130 (L3) is included within the third resonator, with reference numerals 1110, 1120, and 1130 identifying the outer boundaries of the layout of inductors L1, L2, and L3, respectively. As can be seen in this first example, the inductors 1110, 1120, 1130 (L1, L2, L3) of the filter 1100 are spaced apart, resulting in a small magnetic coupling coefficient. As a result, the coupling of the resonators is primarily electrical and is defined by the capacitance between the resonators. In the embodiment of Figure 11, the coupling coefficient between the inductors 1110, 1120, 1130 (L1, L2, L3) is small (i.e., approximately 10 m or less).

[0046]

[0085] Consistent with the circuit element nomenclature of Figure 6, the third-order resonator filter 1100 of Figure 11 can be seen to include a first capacitance 1150 (C1) proximate to a first inductor 1110 (L1). The filter 1100 also includes several capacitances proximate to a second inductor 1120 (L2): a second capacitance 1160 (C12), a third capacitance 1170 (C2), and a fourth capacitance 1180 (C23). In the embodiment of Figure 11, the filter 1100 is designed such that the capacitance C3 of the third-order coupled resonator filter 600 of Figure 6 has a value of zero and is therefore not shown in the layout of Figure 11.

[0047]

[0086] 12 illustrates an example layout of inductors for a third-order resonator filter 1200 that combines electrical and magnetic coupling. As shown, a first inductor 1210 (L1) is included within the first resonator, a second inductor 1220 (L2) is included within the second resonator, and a third inductor 1230 (L3) is included within the third resonator, with reference numerals 1210, 1220, and 1230 identifying the outer boundaries of the layout of inductors L1, L2, and L3, respectively. In the example of FIG. 12, the second inductor 1220 (L2) and the third inductor 1230 (L3) are laid out adjacent to each other, resulting in both electrical and magnetic coupling. Meanwhile, the first and second resonators are separated by a relatively large distance (i.e., the separation between the first inductor 1210 (L1) and the second inductor 1220 (L2) is substantially greater than the minimum separation between the second inductor 1220 (L2) and the third inductor 1230 (L3). As a result, the coupling between the first and second resonators is achieved almost entirely by electrical coupling. This is supported by characterizing the coupling coefficients between the inductors 1210, 1220, and 1230 through electromagnetic simulations, which yielded, as expected, almost entirely electrical couplings k12=-7m, k23=-100m, and k13=-5m between the first and second resonators and between the second and third resonators. The layout of FIG. 12 shows only the three inductances L1, L2, and L3 present in the coupled resonator 600 of FIG. 6.

[0048]

[0087] 13, an exemplary layout of a third-order resonator filter 1300 combining electrical and magnetic coupling is illustrated. As shown, a first inductor 1310 (L1) is included within the first resonator, a second inductor 1320 (L2) is included within the second resonator, and a third inductor 1330 (L3) is included within the third resonator, with reference numerals 1310, 1320, and 1330 identifying the conductive trace elements of inductors L1, L2, and L3, respectively. In the resonator filter 1300, all three inductors 1310, 1320, and 1330 (L1, L2, and L3) are laid out in close proximity to one another. This proximity between inductors 1310, 1320, 1330 (L1, L2, L3) results in magnetic coupling between the first, second, and third resonators of filter 1300, which is supplemented with electrical coupling to achieve the desired filter transfer function. The coupling coefficients between inductors 1310, 1320, 1330 (L1, L2, L3) are characterized through electromagnetic simulation as follows: k12 = -93 m, k23 = -111 m, and k13 = -10 m. As can be seen, the layout of third-order resonator filter 1300 is much more area-efficient than that of filter 1100 (FIG. 11).

[0049]

[0088] Consistent with the circuit element nomenclature of FIG. 6, the third-order resonator filter 1300 of FIG. 13 can be seen to include a first capacitance 1350 (C1) proximate to a first inductor 1310 (L1). The filter 1300 also includes a second capacitance 1360 (C12) proximate to the first capacitance 1350 (C1) and a third capacitance 1370 (C2) proximate to the second inductor 1320 (L2). A fourth capacitance 1380 (C23) is interposed between the inductors 1320 (L2) and 1330 (L3). A fifth capacitance 1390 (C3) and a sixth capacitance 1394 (Cms_out) are proximate to the third inductor 1330 (L3).

[0050]

[0089] 14-18, coupled resonator filters are illustrated that have even more area-efficient layouts than that of filter 1300. This area efficiency is achieved by laying out the inductors in these filters so that they at least partially overlap one another.

[0051]

[0090] 14 illustrates an example layout of a third-order resonator filter 1400 having only magnetic coupling. The first resonator of the resonator filter 1400 includes a first inductor 1410 (L1), the second resonator includes a second inductor 1420 (L2), and the third resonator includes a third inductor 1430 (L3), where reference numerals 1410, 1420, and 1430 identify the conductive trace elements of inductors L1, L2, and L3, respectively. The coupling coefficients between the inductors 1410, 1420, and 1430 of the third-order resonator filter 1400 are characterized by electromagnetic simulation as follows: k12=-480 m, k23=-480 m, and k13=-24 m.

[0052]

[0091] Consistent with the circuit element nomenclature of FIG. 6, the third-order resonator filter 1400 of FIG. 14 is seen to include a first capacitance 1450 (C1) adjacent to the first inductor 1410 (L1). The filter 1400 also includes a second capacitance 1460 (C2) interposed between the inductors 1410 (L1) and 1430 (L3). A third capacitance 1470 (C3) and a fourth capacitance 1480 (Cms_out) are adjacent to the third inductor 1430 (L3). In the embodiment of FIG. 14, the filter 1400 is designed such that the capacitances C12 and C23 of the third-order coupled resonator filter 600 of FIG. 6 have values ​​of zero and are therefore not shown in the layout of FIG. 14.

[0053]

[0092] FIG. 15 illustrates an example layout of a second-order resonator filter 1500 having only magnetic coupling. The first resonator of the resonator filter 1500 includes a first inductor 1510 (L1), and the second resonator includes a second inductor 1520 (L2), where reference numerals 1510 and 1520 identify the conductive trace elements of inductors L1 and L2, respectively. The coupling coefficient k12 of the inductors 1510 and 1520 of the second-order resonator filter 1500 is characterized by electromagnetic simulation as follows: k12 = −240 m. As can be seen from FIG. 15, in the filter 1500, the inductors 1510 (L1) and 1520 (L2) only partially overlap to achieve the desired coupling coefficient between its two resonators.

[0054]

[0093] Consistent with the circuit element nomenclature of Figure 6, the third-order resonator filter 1500 of Figure 15 can be seen to include a first capacitance 1550 (C1) proximate to a first inductor 1510 (L1). The filter 1500 also includes a second capacitance 1560 (C2) and a third capacitance 1570 (Cms_out) proximate to a second inductor 1520 (L2). In the embodiment of Figure 15, the filter 1500 is designed such that the capacitance C12 of the third-order coupled resonator filter 600 of Figure 6 has a value of zero and is therefore not shown in the layout of Figure 15.

[0055]

[0094] 16 illustrates an example layout of inductances for a third-order resonator filter 1600 having only magnetic coupling. The first resonator of the resonator filter 1600 includes a first inductor 1610 (L1), the second resonator includes a second inductor 1620 (L2), and the third resonator includes a third inductor 1630 (L3). In FIG. 16, reference numerals 1610 and 1630 identify the outer boundaries of the layout of inductors L1 and L3, respectively, and reference numeral 1620 identifies the conductive trace element of inductor L2.

[0056]

[0095] FIG. 17 illustrates an example layout of inductances for a third-order resonator filter 1700 having only magnetic coupling. The first resonator of the resonator filter 1700 includes a first inductor 1710 (L1), the second resonator includes a second inductor 1720 (L2), and the third resonator includes a third inductor 1730 (L3). In FIG. 17, reference numerals 1710 and 1730 identify the conductive traces in the layout of inductors L1 and L3, respectively, and reference numeral 1720 identifies the outer boundary of inductor L2. The coupling coefficients between the inductors 1710, 1720, and 1730 of the third-order resonator filter 1700 are characterized by electromagnetic simulation as follows: k12=-297m, k23=-297m, and k13=-23m. 16 and 17 only show the three inductances L1, L2, L3 present in the third-order coupled resonator filters with magnetic coupling, i.e., the capacitances in the coupled resonator filters 1600, 1700 are not shown.

[0057]

[0096] 18 illustrates an example layout of a third-order resonator filter 1800 having only magnetic coupling. The first resonator of the resonator filter 1800 includes a first inductor 1810 (L1), the second resonator includes a second inductor 1820 (L2), and the third resonator includes a third inductor 1830 (L3). In FIG. 18, reference numerals 1810, 1820, and 1830 identify path markings superimposed on the conductive traces forming inductors L1 and L3, respectively.

[0058]

[0097] Consistent with the circuit element nomenclature of FIG. 6, the third-order resonator filter 1800 of FIG. 18 can be seen to include a first capacitance 1850 (C1) proximate to the first inductor 1410 (L1). The filter 1400 also includes a second capacitance 1860 (C2) located within the lower left corner of the layout of FIG. 18. A third capacitance (C3) is not shown in FIG. 18 because it corresponds to the input capacitance of the LNA connected to the filter 1800. In the embodiment of FIG. 18, the filter 1800 is designed such that the capacitances C12 and C23 present in the third-order coupled resonator filter 600 of FIG. 6 have zero values ​​and are therefore not shown in the layout of FIG. 18. A fourth capacitance 1880 (C3g) is placed in series with the ground connection of the third inductor 1830 (L3) to create an additional notch.

[0059]

[0098] FIG. 19 illustrates the results of an electromagnetic simulation of the third-order resonator filter 1800 of FIG. 18. Specifically, FIG. 19 shows the first coupling coefficient k12 between inductors L1 and L2, the second coupling coefficient k23 between inductors L2 and L3, and the third coupling coefficient k13 between inductors L1 and L3 of filter 1800. As can be seen from FIG. 19, magnetic coupling is strong between adjacent overlapping resonators and weak between non-adjacent resonators. That is, k12 and k23 are relatively large because the overlap between L1 / L2 and L2 / L3 is large, while k13 is relatively small because there is no overlap between L1 and L3. This is consistent with the electromagnetic simulation results of the coupling coefficients in FIG. 19, i.e., k12 = −420 m, k23 = −448 m, and k13 = −63 m.

[0060]

[0099] In addition to being area efficient, another advantage of the coupled resonator filters with only magnetic coupling described herein is the ease with which the center frequency and bandwidth of such filters can be programmed. Because capacitors are connected to the filter in a shunt manner, it is easy to add additional capacitance through MOS switches connected to ground to achieve desired center frequency and bandwidth parameters.

[0061]

[0100] When magnetic coupling is introduced between the first and third inductors of the coupled resonator filter of the present disclosure, the signal fed through the second intermediate inductor is added to the signal fed to the output having magnetic coupling between the first and last inductor, and at a specific frequency these two signals are added with opposite phases, resulting in a notch at that specific frequency.

[0062]

[0101] Referring now to FIG. 20, a typical notch frequency response 2000 of a circuit including a third-order resonator filter and an LNA is illustrated. It can be seen in FIG. 20 that the response 2000 includes the gain from the LNA, which is approximately 20 dB. As shown in the frequency response 2000 of FIG. 20, a frequency response notch 2010 is tuned to be located at 2.5 GHz. The location of this frequency response notch can be selected by selecting the appropriate magnetic coupling between the first and last resonators, i.e., the resonators L1 and L3, in the coupled resonator filter described herein. Referring to FIG. 21, a comparison is shown between the measured frequency response 2100A and the simulated frequency response 2100B of the receiver of FIG. 5 implemented using a coupled resonator filter configured to generate a notch frequency response. As shown, the measured frequency response 2100A and the simulated frequency response 2100B include a first frequency response notch 2110 and a second frequency response notch 2120, respectively. According to the present disclosure, the relative signs (polarities) of the coupling coefficients of a coupled resonator filter are set to specific relative values ​​to achieve the signal path cancellation necessary to produce this notched frequency response. That is, unless the coupling between the various inductors in the coupled resonators is of the correct sign, such signal cancellation will not occur and a notch will not be produced in the frequency response. For example, in the embodiment of FIG. 18, filter 1800 is configured such that all coupling coefficients (k12, k23, k13) are negative. However, if filter 1800 were configured such that k12 and k23 remained negative while the coupling from the first resonator to the last resonator (k13) was selected to have the opposite sign, a frequency response notch such as notch 2010 in FIG. 20 would not be present in the frequency response of filter 1800. Rather, configuring a resonator filter with k12 having the opposite sign would require k13 to be positive to achieve the signal path cancellation necessary to produce the notched frequency response. Finally, it is noted that the input impedance of the LNA loading the filter can be chosen arbitrarily, since a match between the source impedance and the LNA input impedance can be included in the filter.This makes it possible to design an LNA with an optimal input impedance from a noise standpoint.

[0063]

[0102] More broadly, it has been found that the frequency response of the coupled resonator filter described herein includes a notch when the values ​​of the first, second, and third coupling coefficients satisfy predetermined conditions. The predetermined conditions include a condition that the first, second, and third coupling coefficients are negative. The predetermined conditions also include a condition that the first and second coupling coefficients are positive and the third coupling coefficient is negative. The predetermined conditions further include a condition that the first and second coupling coefficients are of opposite polarity and the third coupling coefficient is positive. The predetermined conditions also include a condition that the absolute values ​​of the first and second coupling coefficients are greater than 0.25 and the absolute value of the third coupling coefficient is less than 0.25. It has further been found that such a notch is included in the frequency response of the coupled resonator filter at a frequency that depends on the value of the third coupling coefficient and the product of the first and second coupling coefficients.

[0064]

[0103] Finally, it should be noted that the input impedance of the LNA loading the coupled resonator filter can be chosen arbitrarily, since the filter can be designed to include matching to match the source impedance with the LNA input impedance, making it possible to design an LNA with an input impedance that is optimal from a noise point of view.

[0065] On-chip coupled resonator filter combined with LNA

[0104] Attention is now directed to FIGS. 22 and 23, which illustrate active filter circuits 2200 and 2300. As shown in FIG. 22, active filter circuit 2200 is comprised of a coupled-resonator filter 2204 combined with a source-degenerated LNA 2208. Similarly, in FIG. 23, active filter circuit 2300 is seen to include a coupled-resonator filter 2304 and a source-degenerated LNA 2308. It has been found that when an on-chip coupled resonator as described herein is connected to a conventional source-degenerated LNA 300 of the type shown in FIG. 3, the gate capacitance of the input stage 310 of LNA 300 can be used as the capacitance of the third resonator of the coupled-resonator filter. See, for example, capacitance C3 of circuits 2200 (FIG. 22) and 2300 (FIG. 23). Making the LNA input devices 2210, 2310 an integrated part of filters 2200, 2300 has the advantages of improved noise performance and reduced die area. A bias voltage is applied to the gates of the input devices 2210, 2310 through inductance L3.

[0066]

[0105] Figure 2 illustrates a source-gated feedback LNA topology 200 that can be used, for example, as an alternative to the source-degenerated LNA topologies of Figures 22 and 23. An exemplary circuit implementing this technique is depicted in Figure 24, which schematically illustrates an active filter circuit 2400.

[0067]

[0106] Referring to Figure 24, active filter circuit 2400 consists of a coupled resonator filter 2404 in combination with a source-gate feedback LNA 2408. As can be seen from Figure 24, coupled resonator filter 2404 relies solely on magnetic coupling, i.e., the values ​​of coupling ratios k12, k13, and k23 are determined exclusively by the configuration of inductive elements L1, L2, and L3 within filter 2404.

[0068]

[0107] 31 and 33 illustrate exemplary CMOS implementations of source-gated feedback LNA topologies 3100, 3300 that can be used as alternatives to the source-degenerated topologies described herein. In the exemplary implementation of FIG. 33, the exemplary topology 3300 is configured for distortion cancellation and includes a source-gated feedback LNA 3310 and a distortion cancellation network 3320.

[0069]

[0108] 26 schematically illustrates an active filter 2600 having a coupled resonator filter 2604 in combination with a source-gated feedback LNA 2608 configured to produce a frequency response with an input notch circuit (Ln, Cn in). As shown, the input notch circuit (Ln, Cn in) is connected to the input source and can be utilized if additional low-frequency attenuation is required.

[0070]

[0109] FIG. 28 illustrates the frequency responses of filter and LNA implementations with and without an additional input notch circuit: frequency response 2810 of a filter having the topology of active filter 2600, and frequency response 2820 of a substantially identical filter without the input notch circuit (Ln, Cn in). In FIG. 28, active filter 2600 was implemented by selecting values ​​for the notch circuit (Ln, Cn in) such that the input notch in the frequency response occurs at approximately 1.7 GHz. As can be seen from FIG. 28, this results in improved low-frequency attenuation, as illustrated in FIG. 28 (comparing frequency response 2820 (yellow dotted line) to frequency response 2810 (orange line)). When a source-gate feedback topology is used in an LNA, a second frequency response notch can be created by adding a notch circuit consisting of a capacitor in series with the gate inductance of the LNA. See, for example, active filter circuits 2500, 2600, and 2700 of FIGS. 25-27. In these circuits, the notch capacitance Cn is connected in series with the gate inductance Lg of each LNA input device 2510, 2610, 2710.

[0071]

[0110] Referring to FIG. 25, an active filter 2500 includes a coupled resonator filter 2504 with only magnetic coupling, in combination with a source-gate feedback LNA 2508 and an input notch circuit (Lg, Cn).

[0072]

[0111] 27, an active filter 2700 includes a source-gate feedback LNA 2708, an input notch circuit (Lg, Cn) and a coupled resonator filter with only magnetic coupling 2704 in combination with a coupled resonator filter with only magnetic coupling 2720 (with a coupling coefficient k45) at the output of the filter 2700. The wideband matching achieved when a coupled resonator filter is added to the output of the LNA (as depicted in FIG. 27) is shown in FIG.

[0073]

[0112] 32A and 32B illustrate the area efficiency improvements possible using magnetically coupled resonator filters according to the present disclosure. Specifically, FIG. 32A depicts an example layout 3200A of an electrically coupled resonator filter and a source-degenerated LNA, and FIG. 32B shows an example layout 3200B of a magnetically coupled resonator filter and a source-degenerated LNA. The examples in FIGS. 32A and 32B show that area reductions of approximately 30-40% can be achieved by using resonators that rely essentially exclusively on magnetic coupling. It can be seen that further area savings are possible with further optimization.

[0074] Programmable coupled resonator filters.

[0113] Having a coupled resonator filter with only magnetic coupling allows for easy band programming of the filter, which is useful in receivers where the filter response can be tuned to a band of interest. The frequency response of the receiver of Figure 5 implemented with a coupled resonator filter with only magnetic coupling that is programmable to receive two different frequency bands (Wi-Fi 6 from 5 to 6 GHz and Wi-Fi 6E from 6 to 7 GHz) is shown in Figure 30.

[0075]

[0114] To make a filter programmable, the capacitors in the filter must be tuned so that different capacitance values ​​can be achieved by switching additional capacitance in or out of the filter. This is preferable to switching in or out inductance, which is bulky and takes up a large die area. Switches in silicon technologies are generally chosen to be either PMOS or NMOS, based on which is easiest to program when the source of the switch is connected to signal ground. Therefore, it is preferable for the capacitance to be programmed to be grounded at one of the terminals of the switch.

[0076]

[0115] Referring now to FIG. 34, an exclusive magnetically coupled resonator filter 3400 is shown, including two coupled resonators 3410, 3420 and a notch circuit 3430 at the output. In the embodiment of FIG. 34, all capacitances (C) are programmable and connected to ground. FIG. 36 illustrates an exemplary capacitor filter bank 3600 of a type that may be used to implement the programmable capacitances in the filter 3400. The frequency responses 3510, 3520 of the filter 3400 when programmed for either the WiFi-6 (5-6 GHz) or WiFi-6E (6-7 GHz) frequency bands, respectively, are shown in FIG. 35. As can be seen from FIG. 35, the frequency response notches 3510n, 3520n generated by the notch circuit 3430 are centered in the low band below the passband when the filter is tuned to the high band, and vice versa.

[0077]

[0116] During operation of the filter 3400, the notch circuit 3430 facilitates tuning of the output resonator 3420. When the notch circuit 3530 is tuned below the passband, the notch circuit 3430 is inductive within the passband, requiring extra parallel capacitance as compensation. This is because, at the same time, minimal capacitance within the resonator 3420 is required to tune it to high frequencies, thus reducing the required tuning range of the capacitor bank 3600 of the output resonator 3420. In other embodiments, a second notch circuit can be installed on the other side of the filter (e.g., in parallel with the resonator 3410) to improve attenuation.

[0078] A mathematical framework for filter parameter calculations.

[0117] While it is not necessary for one skilled in the art to make and use the disclosed coupled resonator filters and the disclosed combinations of such filters and low noise amplifiers, the following is a mathematical framework that demonstrates an exemplary approach to calculating parameters. In particular, the following mathematical framework describes the parameter calculations used in spreadsheet 1000 of FIG. 10, with each calculated cell in spreadsheet 1000 described below.

[0079]

[0118] Input parameters: f0 [MHz] is the center frequency of the filter. BW [MHz] is the bandwidth of the filter. Ripple [dB] is the target in-band filter ripple. RS [Ω] and RL [Ω] are the target source impedance and the target load impedance, respectively. The percentage of maximum coupling coefficient is the amount of magnetic coupling, with 100% meaning only magnetic coupling and 0% meaning only electrical coupling. L1[H], L2[H] and L3[H] are the target inductance values ​​of the three resonators.

[0080]

[0119] Calculated parameters:

number

number

number

number

[0081]

[0120] This capacitance value is shown in grey in spreadsheet 1000 as it is used for calculation purposes only. Cms_in and Cms_out are the matching capacitances required for impedance matching between the source impedance and the impedance level of the first resonator and between the load impedance and the impedance level of the last resonator, respectively. C1[F], C2[F], and C3[F] are calculated from the other capacitance values: C1[F]=C1res-C12-Cmsp_in, C1[F]=C2res-C12-C23, and C3[F]=C3res-C23-Cmsp_out C12max [F] and C23max [F] are the coupling capacitors between the resonators when only electrical coupling is used and are calculated from the following formula:

number

[0082]

[0121] When only magnetic coupling is used, k12max and k23max are the coupling coefficients between the inductances of the first and second resonators and between the inductances of the second and third resonators, respectively, and are calculated from the following equations:

number

[0083]

[0122] The effective coupling ratio and capacitance between the resonators is calculated from the linear ratio of the percentage of the maximum coupling coefficient.

number

number

[0084]

[0123] The equations k12max, k23max, C12[F], C23[F], k12, and k23 have been derived by the present inventors. The equations used in the spreadsheet 1000 of Figure 10 are taken from the book "Microwave Filters for Communication Systems" by Richard J. Cameron et al. Unless otherwise noted, all other equations are found in the publication entitled "The Design of Direct Coupled Band Pass Filters," published July 10, 2016, by Iowa Hills Software (IowaHills.com).

[0085]

[0124] Described herein are integrated magnetoelectrically coupled resonator filters that offer many improvements over existing filters. A key novel feature of the integrated magnetoelectrically coupled resonator filters described herein is the area-efficient layout when coupling between inductors can be used as part of the intended design rather than being unnecessary. Additionally, inductors can be laid out in an overlapping manner to exclusively create magnetic coupling. Inductors can also be laid out adjacent to each other, allowing insufficient magnetic coupling to be supplemented with electrical coupling to establish the intended filter transfer function.

[0086]

[0125] Another important novel feature is that the coupling between the first and last resonators creates a notch that can be used to suppress unwanted signals at specific frequencies. Additionally, if the impedance level of the first resonator is chosen to be the same as the source impedance, the first inductor can be used as ESD protection.

[0087]

[0126] It can further be appreciated that the disclosed filters can be used for impedance transformation to an LNA for optimal noise performance. Additionally, the use of exclusively magnetic coupling simplifies tuning of the filters.

[0088]

[0127] Also described herein are novel configurations of on-chip coupled resonator filters in combination with LNAs. It will be appreciated that the teachings of this disclosure extend to embodiments in which the LNA is replaced with other types of amplifiers, such as a power amplifier. In connection with these configurations, the inventors unexpectedly discovered that the gate capacitance of the LNA can be an integrated part of the filter. Furthermore, the inventors discovered that using a shunt gate inductance at the input of the LNA improves low-frequency attenuation. Additionally, it has been found that adding a series capacitance to the gate inductance of the LNA can create notches to increase attenuation at specific frequencies. Furthermore, adding an additional series resonant circuit in parallel with one of the resonators in the filter can create notches to increase attenuation at specific frequencies.

[0089]

[0128] In certain embodiments, on-chip resonator filters can be added to both the input and output of the LNA to provide wideband matching. Coupled resonator filters can be used to convert single-ended signals to differential signals without adding additional passive components. Coupled resonator filters can also be used to convert differential signals to single-ended signals without adding additional passive components.

[0090]

[0129] The present disclosure also relates to a novel programmable magnetic-only coupled resonator filter combined with a notch circuit. The disclosed magnetic-only coupled filter utilizes a programmable capacitance with one terminal connected to ground, making it easy to program. Additionally, the notch circuit narrows the tuning range of the programmable capacitance.

[0091]

[0130] Where the above method indicates that certain events occur in a particular order, this ordering of the specific events may be modified. In addition, some of the events may be performed simultaneously in a parallel process, where possible, rather than just sequentially as described above. Therefore, this specification intends to cover all such modifications and variations of the disclosed embodiments that fall within the spirit and scope of the appended claims.

[0092]

[0131] In the foregoing description, for purposes of explanation, specific nomenclature was used to provide a thorough understanding of the claimed systems and methods. However, it will be apparent to those skilled in the art that specific details are not required to practice the systems and methods described herein. Thus, the foregoing descriptions of specific embodiments of the described systems and methods have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the scope of the claims to the precise forms disclosed, and obviously, many modifications and variations are possible in light of the above teachings. The embodiments were chosen and described to best explain the principles of the described systems and methods and their practical application, so as to enable those skilled in the art to make full use of the described systems and methods and various embodiments with various modifications as suited to the particular use contemplated. The following claims and their equivalents are intended to define the scope of the systems and methods described herein.

[0093]

[0132] Various inventive concepts may also be embodied as one or more methods, examples of which are provided. The acts performed as part of a method may be ordered in any suitable manner. Thus, while an example embodiment shows acts as sequential, embodiments may be constructed in which the acts are performed in a different order than illustrated, and may include performing some acts simultaneously.

[0094]

[0133] All definitions defined and used herein shall be understood to take precedence over dictionary definitions, definitions in documents incorporated by reference, and / or ordinary meanings of the defined terms.

[0095]

[0134] The indefinite articles "a" and "an," as used in this specification and claims, unless expressly indicated to the contrary, shall be understood to mean "at least one."

[0096]

[0135] The term "and / or," as used in the specification and claims, shall be understood to mean "either or both" of the elements so coordinating, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with "and / or" shall be construed similarly, i.e., "one or more" of the elements so coordinating. Other elements may optionally be present other than the elements specifically identified by the "and / or" clause, whether related to those specifically identified elements or not. Thus, as a non-limiting example, a reference to "A and / or B," when used in conjunction with open-ended language such as "comprising," may, in one embodiment, refer to A only (optionally including elements other than B); in another embodiment, refer to B only (optionally including elements other than A); in yet another embodiment, refer to both A and B (optionally including other elements); and so forth.

[0097]

[0136] As used in this specification and the claims, "or" shall be understood to have the same meaning as "and / or" as defined above. For example, when separating items in a list, "or" or "and / or" shall be interpreted as being inclusive, i.e., including not only at least one of the elements or listed elements, but also two or more of the elements or listed elements and, optionally, additional items not in the list. Only terms clearly indicating the contrary, such as "only one of" or "exactly one of," or, when used in the claims, "consisting of," shall mean including exactly one of the elements or listed elements. Generally, the term "or" as used herein shall be interpreted to indicate exclusive alternatives (i.e., "one or the other, but not both") only when preceded by terms of exclusion, such as "either," "one of," "only one of," or "exactly one of." When used in the claims, "consisting essentially of" shall have its ordinary meaning as used in the field of patent law.

[0098]

[0137] As used in this specification and claims, the phrase "at least one," in reference to a list of one or more elements, is understood to mean at least one element selected from any one or more of the elements in the list of elements, but does not necessarily include at least one of every element specifically listed in the list of elements, and does not exclude any combination of elements in the list of elements. This definition also allows for the optional presence of elements other than those specifically identified in the list of elements to which the phrase "at least one" refers, whether related to those specifically identified elements or not. Thus, as a non-limiting example, "at least one of A and B" (or equivalently, "at least one of A or B" or equivalently, "at least one of A and / or B") can refer in one embodiment to at least one A, optionally including more than one, with no B (and optionally including elements other than B); in another embodiment to at least one B, optionally including more than one, with no A (and optionally including elements other than A); in yet another embodiment to at least one A, optionally including more than one, and at least one B (and optionally including other elements), optionally including more than one; etc.

[0099]

[0138] As in the specification above, in the claims, transitional phrases such as "comprise," "include," "carry," "have," "contain," "accompany," "hold," "comprise," and the like are all to be understood to be open-ended, i.e., meaning including but not limited to. Only the transitional phrases "consisting of" and "consisting essentially of" shall be closed-ended or semi-closed-ended transitional phrases, respectively, as defined in the United States Patent Office Manual of Patent Examining Procedures 2111.03.

Claims

1. It is a coupled resonator filter, A first parallel resonator including a first capacitance connected in parallel with a first inductance, A second parallel resonator including a second capacitance connected in parallel to the second inductance, A third parallel resonator including a third capacitance connected in parallel with a third inductance, A series resonant circuit connected in parallel to any of the first parallel resonator, the second parallel resonator, and the third parallel resonator, wherein the frequency response of the coupled resonator filter includes an additional notch at a frequency that depends on the resonant frequency of the series resonant circuit, Equipped with, The magnetic coupling between the first inductance and the second inductance magnetically couples the first parallel resonator and the second parallel resonator according to a first coupling coefficient. The magnetic coupling between the second inductance and the third inductance magnetically couples the second parallel resonator and the third parallel resonator according to the second coupling coefficient. The magnetic coupling between the first inductance and the third inductance magnetically couples the first parallel resonator and the third parallel resonator according to the third coupling coefficient. A coupled resonator filter in which the frequency response of the coupled resonator filter includes a notch when the values ​​of the first coupling coefficient, the second coupling coefficient, and the third coupling coefficient satisfy predetermined conditions.

2. The coupled resonator filter according to claim 1, wherein the predetermined condition includes a condition specifying that the notch is included in the frequency response of the coupled resonator filter at a frequency that depends on the value of the third coupling coefficient and the product of the first coupling coefficient and the second coupling coefficient.

3. The coupled resonator filter according to claim 1, further comprising a first coupling capacitance connected between the first parallel resonator and the third parallel resonator, which capacitively couples the first parallel resonator and the third parallel resonator.

4. The coupled resonator filter according to claim 3, further comprising a second coupling capacitance connected between the first parallel resonator and the second parallel resonator, which capacitively couples the first parallel resonator and the second parallel resonator.

5. The coupled resonator filter according to claim 4, further comprising a third coupling capacitance connected between the second parallel resonator and the third parallel resonator, which capacitively couples the second parallel resonator and the third parallel resonator.

6. The coupled resonator filter according to claim 1, wherein the predetermined conditions include the condition that the first coupling coefficient, the second coupling coefficient, and the third coupling coefficient are negative.

7. The coupled resonator filter according to claim 1, wherein the predetermined conditions include the condition that the first coupling coefficient and the second coupling coefficient are positive and the third coupling coefficient is negative.

8. The coupled resonator filter according to claim 1, wherein the predetermined conditions include the condition that the first coupling coefficient and the second coupling coefficient are of opposite polarity and the third coupling coefficient is positive.

9. The coupled resonator filter according to claim 1, wherein the predetermined conditions include the condition that the absolute value of the first coupling coefficient and the absolute value of the second coupling coefficient are greater than 0.25, and the absolute value of the third coupling coefficient is less than 0.

25.

10. The first coupling coefficient is characterized by the first coupling coefficient k12, [Math 1] The second coupling coefficient is characterized by the second coupling coefficient k23, [Math 2] [Math 3] f0 is the center frequency of the filter, BW is the bandwidth of the filter, The coupled resonator filter according to claim 1, wherein g1, g2, and g3 are filter prototype values.

11. A first parallel resonator including a first capacitance connected in parallel with a first inductance, A second parallel resonator including a second capacitance connected in parallel to the second inductance, A third parallel resonator including a third capacitance connected in parallel with a third inductance, A first coupling capacitance is connected between the first parallel resonator and the third parallel resonator, capacitively coupling the first parallel resonator and the third parallel resonator, A second coupling capacitance is connected between the first parallel resonator and the second parallel resonator, capacitively coupling the first parallel resonator and the second parallel resonator, Equipped with, The magnetic coupling between the first inductance and the second inductance magnetically couples the first parallel resonator and the second parallel resonator according to a first coupling coefficient. The magnetic coupling between the second inductance and the third inductance magnetically couples the second parallel resonator and the third parallel resonator according to the second coupling coefficient. The magnetic coupling between the first inductance and the third inductance magnetically couples the first parallel resonator and the third parallel resonator according to the third coupling coefficient. When the values ​​of the first coupling coefficient, the second coupling coefficient, and the third coupling coefficient satisfy predetermined conditions, the frequency response of the coupled resonator filter includes a notch. The maximum absolute value of the magnetic coupling between the first inductance and the second inductance is characterized by the first maximum coupling coefficient k12max, The maximum magnetic coupling between the second inductance and the third inductance is characterized by the second maximum coupling coefficient k23max, [Math 4] [Formula 5] [Math 6] [Number 7] [Number 8] k12 is the percentage of k12max that exists between the first inductance and the second inductance. k23 is the percentage of k23max that exists between the second inductance and the third inductance. f0 is the center frequency of the filter, BW is the bandwidth of the filter, g1, g2, and g3 are filter prototype values, A coupled resonator filter in which C12max and C23max are coupling capacitances connected between the first parallel resonator and the second parallel resonator, and between the second parallel resonator and the third parallel resonator, respectively, when no magnetic coupling exists.

12. A first parallel resonator including a first capacitance connected in parallel with a first inductance, A second parallel resonator including a second capacitance connected in parallel to the second inductance, A series resonant circuit connected in parallel to either the first parallel resonator or the second parallel resonator, wherein the frequency response of the coupled resonator filter includes an additional notch at a frequency that depends on the resonant frequency of the series resonant circuit, Equipped with, The first inductance and the second inductance are mounted on multiple layers of the integrated circuit and overlap at least partially. An integrated circuit coupled resonator filter wherein the magnetic coupling between the first inductance and the second inductance magnetically couples the first parallel resonator and the second parallel resonator according to a first coupling coefficient greater than 0.

5.

13. The integrated circuit coupled resonator filter according to claim 12, wherein the first coupling coefficient is greater than 0.

6.

14. The integrated circuit coupled resonator filter according to claim 12, wherein the first coupling coefficient is greater than 0.

7.

15. Further comprising a third parallel resonator including a third capacitance connected in parallel with the third inductance, The magnetic coupling between the second inductance and the third inductance magnetically couples the second parallel resonator and the third parallel resonator. The integrated circuit coupled resonator filter according to claim 12, wherein the magnetic coupling between the first inductance and the third inductance magnetically couples the first parallel resonator and the third parallel resonator.

16. A coupling N-order resonator filter comprising, the coupling N-order resonator filter comprising N parallel resonators arranged in a series, wherein N is at least 3, At a first frequency that depends on the coupling characteristics between discontinuous parallel resonators among the N parallel resonators, the frequency response of the coupled resonator filter arrangement includes a first notch. A coupled resonant filter arrangement further comprising a series resonant circuit connected in parallel to any of the N parallel resonators, wherein the frequency response of the coupled resonant filter arrangement includes a second notch at a second frequency that depends on the resonant frequency of the series resonant circuit.

17. The coupled resonator according to claim 16, wherein the discontinuous parallel resonator includes a first parallel resonator among the N parallel resonators and a third parallel resonator among the N parallel resonators, and the second parallel resonator among the N parallel resonators is interposed between the first parallel resonator and the third parallel resonator.

18. The first parallel resonator includes a first capacitance connected in parallel with the first inductance, The second parallel resonator includes a second capacitance connected in parallel with the second inductance, The third parallel resonator includes a third capacitance connected in parallel with the third inductance, The magnetic coupling between the first inductance and the second inductance magnetically couples the first parallel resonator and the second parallel resonator according to a first coupling coefficient. The magnetic coupling between the second inductance and the third inductance magnetically couples the second parallel resonator and the third parallel resonator according to the second coupling coefficient. The coupled resonator filter arrangement according to claim 17, wherein the magnetic coupling between the first inductance and the third inductance magnetically couples the first parallel resonator and the third parallel resonator according to a third coupling coefficient.

19. The coupled resonator filter arrangement according to claim 18, wherein the first coupling coefficient, the second coupling coefficient, and the third coupling coefficient are negative.

20. The coupled resonator filter according to claim 18, wherein the first coupling coefficient and the second coupling coefficient are positive, and the third coupling coefficient is negative.

21. The coupled resonator filter according to claim 18, wherein the first coupling coefficient and the second coupling coefficient are of opposite polarity, and the third coupling coefficient is positive.

22. The coupled resonator filter according to claim 18, wherein the absolute values ​​of the first coupling coefficient and the second coupling coefficient are greater than 0.25, and the absolute value of the third coupling coefficient is less than 0.

25.

23. A first parallel resonator including a first capacitance connected in parallel with a first inductance, A second parallel resonator including a second capacitance connected in parallel to the second inductance, A third parallel resonator including a third capacitance connected in parallel with a third inductance, A series resonant circuit connected in parallel to either the first parallel resonator or the second parallel resonator, wherein the frequency response of the coupled resonator filter includes an additional notch at a frequency that depends on the resonant frequency of the series resonant circuit, Equipped with, The magnetic coupling between the first inductance and the second inductance magnetically couples the first parallel resonator and the second parallel resonator according to a first coupling coefficient. The magnetic coupling between the second inductance and the third inductance magnetically couples the second parallel resonator and the third parallel resonator according to the second coupling coefficient. The magnetic coupling between the first inductance and the third inductance magnetically couples the first parallel resonator and the third parallel resonator according to the third coupling coefficient. (i) The first coupling coefficient, the second coupling coefficient and the third coupling coefficient are negative, (ii) The first coupling coefficient and the second coupling coefficient are positive and the third coupling coefficient is negative, and (iii) The first and second coupling coefficients are of opposite polarity, and the third coupling coefficient is positive. A coupled resonator filter whose frequency response includes a notch when at least one of the following conditions is met.

24. The coupled resonator filter according to claim 23, wherein the absolute values ​​of the first coupling coefficient and the second coupling coefficient are greater than the strong coupling threshold, and the absolute value of the third coupling coefficient is less than the weak coupling threshold.

25. The coupled resonator filter according to claim 24, wherein the strong coupling threshold is 0.25 and the weak coupling threshold is 0.1.

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