Systems and methods for cancellation of leakage into a RX port of a duplexer or multiplexer

Systems and methods relating to improving transmit (TX) port to receive (RX) port isolation of a duplexer or multiplexer are disclosed. In some embodiments, a system includes a duplexer or multiplexer having a transmit port, a receive port, and an antenna port. The system further includes a leakage cancellation subsystem adapted to cancel a leakage signal from the TX port of the duplexer or multiplexer to the RX port of the duplexer or multiplexer across a desired cancellation bandwidth. The leakage cancellation subsystem compensates for variation of the leakage signal across the desired cancellation bandwidth, thereby improving TX port to RX port isolation over conventional systems.

FIELD OF THE DISCLOSURE

The present disclosure relates to duplexers and multiplexers and, in particular, to improving transmit (TX) to receive (RX) port isolation of a duplexer or multiplexer.

BACKGROUND

Duplexers (also referred to herein as duplex filters) and multiplexers (also referred to herein as multiplex filters) in modern communications systems require high out-of-band rejection and high isolation from any transmit (TX) to any receive (RX) port. The straightforward way to improve these rejection and isolation requirements is by means of re-optimization of the parameters governing the individual resonator elements in a filter or by increasing the order of the filter topology. Unfortunately, these methods more often than not result in an accompanying increase in in-band insertion loss.

As such, there is a need for systems and methods for improving out-of-band rejection and isolation between TX and RX ports of a duplexer or multiplexer while not impacting in-band insertion loss.

SUMMARY

Systems and methods relating to improving transmit (TX) port to receive (RX) port isolation of a duplexer or multiplexer are disclosed. In some embodiments, a system includes a duplexer or multiplexer having a TX port, a RX port, and an antenna port. The system further includes a leakage cancellation subsystem adapted to cancel a leakage signal from the TX port of the duplexer or multiplexer to the RX port of the duplexer or multiplexer across a desired cancellation bandwidth. The leakage cancellation subsystem compensates for variation of the leakage signal across the desired cancellation bandwidth, thereby improving TX port to RX port isolation over conventional systems.

In some embodiments, the desired cancellation bandwidth is a RX band of a RX filter of the duplexer or multiplexer that couples the antenna port to the RX port. In other embodiments, the desired cancellation bandwidth is a TX band of a TX filter of the duplexer or multiplexer that couples the TX port to the antenna port.

In some embodiments, the variation of the leakage signal across the desired cancellation bandwidth is a variation of both an amplitude and a phase of the leakage signal over the desired cancellation bandwidth.

In some embodiments, the leakage cancellation subsystem includes filtering circuitry having an input coupled to the TX port of the duplexer or multiplexer. The filtering circuitry is adapted to filter a TX signal provided to the TX port of the duplexer or multiplexer to generate a cancellation signal that is a function of (e.g., mimics) an amplitude variation of the leakage signal across the desired cancellation bandwidth and a phase variation of the leakage signal across the desired cancellation bandwidth. In some embodiments, the filtering circuitry includes acoustic elements. In some embodiments, the filtering circuitry includes a Bulk Acoustic Wave (BAW) filter. In other embodiments, the filtering circuitry includes a Surface Acoustic Wave (SAW) filter.

In some embodiments, the leakage cancellation subsystem further includes attenuation and phase adjustment circuitry having an input coupled to an output of the filtering circuitry and an output coupled to the RX port of the duplexer or multiplexer. The attenuation and phase adjustment circuitry is adapted to apply an amplitude offset and a phase offset to the cancellation signal to thereby provide an adjusted cancellation signal that mitigates the leakage signal at the RX port of the duplexer or multiplexer.

In some embodiments, the leakage cancellation subsystem includes filtering circuitry and attenuation and phase adjustment circuitry. The filtering circuitry has an input coupled to the TX port of the duplexer or multiplexer. The filtering circuitry includes acoustic elements and is adapted to filter a TX signal provided to the TX port of the duplexer or multiplexer to generate a cancellation signal that is a function of (e.g., mimics) an amplitude variation of the leakage signal across the desired cancellation bandwidth and a phase variation of the leakage signal across the desired cancellation bandwidth. The attenuation and phase adjustment circuitry has an input coupled to an output of the filtering circuitry and an output coupled to the RX port of the duplexer or multiplexer. The attenuation and phase adjustment circuitry is adapted to apply an amplitude offset and a phase offset to the cancellation signal to thereby provide an adjusted cancellation signal that mitigates the leakage signal at the RX port of the duplexer or multiplexer. In some embodiments, the filtering circuitry includes a BAW filter. In other embodiments, the filtering circuitry includes a SAW filter.

In some embodiments, the duplexer or multiplexer includes a TX filter that couples the TX port to the antenna port and a RX filter that couples the antenna port to the RX port, the desired cancellation bandwidth is a RX band of the RX filter of the duplexer or multiplexer, and the system further includes a second leakage cancellation subsystem adapted to cancel a leakage signal from the TX port of the duplexer or multiplexer to the RX port of the duplexer or multiplexer across a TX band of the TX filter of the duplexer or multiplexer. The second leakage cancellation subsystem compensates for variation of the leakage signal across the TX band. In some embodiments, the duplexer or multiplexer is a duplexer.

In some embodiments, the duplexer or multiplexer is a multiplexer having the TX port, a second TX port, and the RX port. The multiplexer includes a first TX filter that couples the TX port to the antenna port, a second TX filter that couples the second TX port to the antenna port, and a RX filter that couples the antenna port to the RX port. The desired cancellation bandwidth is a RX band of the RX filter of the multiplexer. The system further includes a second leakage cancellation subsystem adapted to cancel a leakage signal from the second TX port of the multiplexer to the RX port of the multiplexer across a TX band of the second TX filter of the multiplexer. The second leakage cancellation subsystem compensates for variation of the leakage signal across the TX band of the second TX filter.

In some embodiments, the duplexer or multiplexer is a multiplexer having the TX port, a second TX port, and the RX port. The multiplexer includes a first TX filter that couples the TX port to the antenna port, a second TX filter that couples the second TX port to the antenna port, and a RX filter that couples the antenna port to the RX port. The desired cancellation bandwidth is a RX band of the RX filter of the multiplexer. The system further includes a second leakage cancellation subsystem including attenuation and phase adjustment circuitry having an input coupled to the second TX port and an output coupled to the RX port. In some embodiments, the attenuation and phase adjustment circuitry is adapted to apply an amplitude offset and a phase offset to a TX signal provided to the second TX port of the multiplexer to thereby provide a cancellation signal that mitigates a leakage signal from the second TX port to the RX port of the multiplexer.

In some embodiments, the duplexer or multiplexer is a duplexer. In other embodiments, the duplexer or multiplexer is a multiplexer.

Embodiments of a method of mitigating a leakage signal from a TX port to a RX port of a duplexer or multiplexer are also disclosed. In some embodiments, the method includes generating a cancellation signal that is a function of (e.g., mimics) an amplitude variation and a phase variation of a leakage signal from a TX port to a RX port of a duplexer or multiplexer across a desired cancellation bandwidth, applying an amplitude offset and a phase offset to the cancellation signal to provide an adjusted cancellation signal, and applying the adjusted cancellation signal to a RX signal output at the RX port of the duplexer or multiplexer to thereby mitigate the leakage signal.

DETAILED DESCRIPTION

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 should be interpreted as having meanings that are consistent with their meanings in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Duplexers and multiplexers in modern communications systems require high out-of-band rejection and high isolation from any transmit (TX) port to any receive (RX) port. The straightforward way to improve these rejection and isolation requirements is by means of re-optimization of the parameters governing the individual resonator elements in a filter or by increasing the order of the filter topology. Unfortunately, these methods more often than not result in an accompanying increase in in-band insertion loss. Another approach is to use feedback circuits that attenuate signals leaking from, for example, the TX port into the RX path; however, these circuits usually provide a narrowband cancellation behavior that does not encompass the respective full operating bands. The present disclosure aims to circumvent this effect.

Before describing embodiments of the present disclosure, a discussion of a conventional duplexer/multiplexer and a conventional approach to cancelling the leakage signal from a TX port to a RX port of the duplexer/multiplexer is beneficial. In this regard,FIG. 1illustrates a duplexer10that includes a TX filter12that couples a TX port14of the duplexer10to an antenna port16of the duplexer10and a RX filter18that couples the antenna port16of the duplexer10to a RX port20of the duplexer10. A multiplexer has a similar architecture, but has, e.g., multiple TX filters each corresponding to a separate TX port and/or multiple RX filters each corresponding to a separate RX port. Since the duplexer10does not have perfect isolation between the TX port14and the RX port20(which is referred to as TX/RX isolation), during operation when a TX signal is provided to the TX port14, a resulting leakage signal passes from the TX port14to the RX port20. The ability of the duplexer10to prevent or attenuate this leakage signal is referred to as the TX/RX isolation of the duplexer10.

A conventional duplexer/multiplexer, such as the duplexer10ofFIG. 1, requires a trade-off between insertion loss and attenuation/isolation. UsingFIG. 1as an example, insertion loss refers to the attention of the TX signal when passing from the TX port14to the antenna port16through the TX filter12of the duplexer10. Everything else being the same, better (higher) TX/RX isolation results in higher insertion loss, and vice versa, better (lower) insertion loss results in worse (lower) TX/RX isolation. For example,FIG. 2illustrates simulation results for one example implementation of the duplexer10ofFIG. 1. The top graph ofFIG. 2illustrates insertion loss over the desired TX frequency band. The bottom graph ofFIG. 2illustrates TX/RX isolation over both the TX band (the frequency band centered at 2,535 megahertz (MHz) in this example) and the RX band (the frequency band centered at 2,655 MHz in this example). Increasing the TX/RX isolation in the RX frequency band increases the insertion loss and, conversely, decreasing the insertion loss decreases the TX/RX isolation in the RX frequency band.

FIG. 3illustrates a conventional system22improving the TX/RX isolation of the duplexer10ofFIG. 1. The conventional system22includes a feedback path24that includes attenuation and phase adjustment circuitry26having an input coupled to the TX port14via a first coupler28and an output coupled to the RX port20via a second coupler30. The approach of the conventional system22to improve over a regular duplexer/multiplexer is simply using an attenuated signal from (e.g., directly from) the TX port14(or alternatively the antenna port16, which may be viewed as an attenuated signal indirectly from the TX port14), which results in narrowband attenuation notches in the isolation. More specifically, the attenuation and phase adjustment circuitry26generates a cancellation signal that is 180° out-of-phase with the leakage signal from the TX port14to the RX port20and having the same amplitude as the leakage signal such that, when the cancellation signal is combined with the RX signal at the second coupler30, the leakage signal is mitigated within the narrowband attenuation notch in the RX band. The narrowband notches can be tuned to different frequency positions by proper adjustment of an attenuation (A) and phase shift (φ) in the feedback path24via the attenuation and phase adjustment circuitry26. As illustrated inFIG. 4, at a given setting (A, φ), only one notch position is possible with one feedback branch. Further, the isolation in the TX frequency band may be affected by lack of frequency selectivity of the feedback path24, as illustrated inFIG. 4.

Using the conventional system22, at any given time, there is only one attenuation (A) adjustment and one phase shift (φ) adjustment (i.e., only one narrowband attenuation notch in the RX band). This may provide satisfactory results if the amplitude and phase of the leakage signal were constant over the RX band (which is the desired cancellation band in this example). However, particularly when using acoustic elements in the TX filter12and the RX filter18of the duplexer10, the leakage signal does not exhibit a constant amplitude and phase over the RX band (i.e., the amplitude and phase of the leakage signal vary across the RX band). Specifically, with respect to the leakage signal, the TX signal passes through the TX filter12and the RX filter18to the RX port20. The TX filter12and the RX filter18have their own passbands having their own passband shapes. The shapes of these passbands dictate the shape of the amplitude variation of the amplitude variation across the RX band. The filter design (e.g., number of resonators used, topology of the filter, other elements (inductors and/or capacitors), spurious modes, etc.) defines the phase variation. This phase variation can be simulated with the filter simulation.

Systems and methods are disclosed herein that mitigate a leakage signal from a TX port to a RX port of a duplexer or multiplexer in such a manner as to account to variation of the leakage signal across a desired cancellation bandwidth (e.g., the RX band). This variation of the leakage signal includes an amplitude variation of the leakage signal across the desired cancellation bandwidth and/or a phase variation of the leakage signal across the desired cancellation bandwidth. In some embodiments, a system is provided that includes a duplexer or multiplexer having a TX port, a RX port, and an antenna port, and a leakage cancellation subsystem adapted to cancel a leakage signal from the TX port of the duplexer or multiplexer to the RX port of the duplexer or multiplexer across a desired cancellation bandwidth. The leakage cancellation subsystem compensates for variation of the leakage signal across the desired cancellation bandwidth.

In this regard,FIG. 5illustrates a system32providing improved TX/RX isolation by compensating for variation of a leakage signal across a desired cancellation bandwidth according to some embodiments of the present disclosure. As illustrated, the system32includes, in this example, a duplexer34that includes a TX filter36that couples a TX port38of the duplexer34to an antenna port40of the duplexer34and a RX filter42that couples the antenna port40of the duplexer34to a RX port44of the duplexer34. The system32also includes a feedback path, which is referred to herein as a leakage cancellation subsystem46, that operates to mitigate, or cancel, a leakage signal that passes from the TX port38to the RX port44of the duplexer34in such a manner as to compensate for, or account for, variation of the leakage signal (e.g., variation of amplitude and/or phase of the leakage signal) across a desired cancellation bandwidth. In this example, the desired cancellation bandwidth is the RX band (i.e., the passband of the RX filter42).

More specifically, the leakage cancellation subsystem46includes a Parallel RX (PRx) filter48, which is also referred to herein as a PRx element, having an input coupled to the TX port38of the duplexer34via a coupler50. Note that while, in this example, the PRx filter48is directly coupled to the TX port38via the coupler50, the present disclosure is not limited thereto. For example, the PRx filter48may alternatively be coupled to the antenna port40(in this manner, the PRx filter48is indirectly coupled to the TX port38via the antenna port40and the TX filter36). Note that the same is true for the other examples of leak cancellation subsystems disclosed herein. In some embodiments, the PRx filter48includes one or more acoustic elements (e.g., an acoustic filter such as, for example, a Bulk Acoustic Wave (BAW) filter that includes one or more BAW resonators or a Surface Acoustic Wave (SAW) filter that includes one or more SAW resonators). Acoustic elements can follow a fast phase response across the frequency of the filter elements of the duplexer34. Note that, in some embodiments, elements (e.g., acoustic elements) of the PRx filter48can be implemented on the same die as the duplexer34(i.e., a monolithic implementation) or implemented on a separate die.

The PRx filter48has a custom-shaped phase response in the feedback path. More specifically, in some embodiments, the PRx filter48has an amplitude and phase response that mimics that of the leakage path (i.e., the path through which the leakage signal propagates from the TX port38to the RX port44) across the desired cancellation bandwidth, which again in this example is the RX band but is not limited thereto. In this manner, the PRx filter48compensates for the variation of the leakage signal across the desired cancellation bandwidth and, as a result, TX/RX isolation is improved.

The leakage cancellation subsystem46also includes attenuation and phase adjustment circuitry52having an input coupled to the output of the PRx filter48and an output coupled to the RX port44of the duplexer34via a coupler54. The leakage cancellation subsystem46operates to apply an attenuation, or amplitude offset, (A) and a phase shift, or phase offset, (φ) to a cancellation signal output by the PRx filter48. The amplitude offset (A) and the phase shift (φ) may, e.g., be dynamically (e.g., adaptively) configured or statically defined.

In operation, a TX signal is provided to the TX port38of the duplexer34. The TX signal is also provided to the PRx filter48via the coupler50. The TX signal leaks from the TX port38through the TX filter36and the RX filter42to the RX port44of the duplexer34. The signal that leaks from the TX port38to the RX port44is the leakage signal. The PRx filter48filters, or processes, the TX signal to thereby generate a cancellation signal having an amplitude and phase variation across the desired cancellation bandwidth that is a function of the amplitude and phase variation of the leakage signal across the desired cancellation bandwidth. In particular, in some embodiments, the PRx filter48filters, or processes, the TX signal to thereby generate the cancellation signal such that the cancellation signal has an amplitude and phase variation across the desired cancellation bandwidth that mimics (e.g., is the same as or at least approximately the same as) the amplitude and phase variation of the leakage signal across the desired cancellation bandwidth. The attenuation and phase adjustment circuitry52applies the amplitude offset (A) and the phase shift (φ) to the cancellation signal to thereby provide an adjusted cancellation signal. The amplitude offset (A) and the phase shift (φ) are selected such that the adjusted cancellation signal is 180° out-of-phase with (or approximately or very near 180° out-of-phase with) the leakage signal and has the same (or approximately the same or very near the same) amplitude. Note that the amplitude offset (A) and the phase shift (φ) are preferably selected such that the phase offset between the adjusted cancellation signal and the leakage is as close to 180° as possible in the particular implementation and that the amplitude of the adjusted cancellation signal is as close as possible to that of the leakage signal in the particular implementation.

FIG. 6illustrates simulation results for TX/RX isolation for one example implementation of the system32ofFIG. 5. As illustrated, in the RX band (which in this example is the frequency band centered at 2,678 MHz), the leakage cancellation subsystem46provides attenuation of the leakage signal across the entire RX band, rather than only in a narrowband notch (as shown for the conventional leakage cancellation system). Thus, cancellation conditions can be met across at least the same bandwidth as the RX filter42and can be met with one A, φ setting. Further, with respect to the TX band (which in this example is the frequency band centered at 2,565 MHz),FIG. 6shows that the leakage cancellation subsystem46has no effect on isolation in the TX band. Also, as shown inFIG. 7, the leakage cancellation subsystem46has no effect on insertion loss in the TX band.

FIG. 8illustrates the system32according to some other embodiments of the present disclosure. In this embodiment, the system32provides improvement of isolation in both the RX and TX bands, and no effect on insertion losses. As illustrated, the system32includes, in this example, the duplexer34, the leakage cancellation subsystem46that operates to mitigate leakage in a first desired cancellation band (the RX frequency band in this example), and a second leakage cancellation subsystem56that operates to mitigate leakage in a second desired cancellation band (the TX frequency band in this example).

The second leakage cancellation subsystem56operates to mitigate, or cancel, a leakage signal in the TX band that passes from the TX port38to the RX port44of the duplexer34in such a manner as to compensate for, or account for, variation of the leakage signal (e.g., variation of amplitude and/or phase of the leakage signal) across the TX band. As illustrated, the second leakage cancellation subsystem56includes a Parallel TX (PTx) filter58, which is also referred to herein as a PTx element, having an input coupled to the TX port38of the duplexer34via a coupler60. In some embodiments, the PTx filter58includes one or more acoustic elements (e.g., an acoustic filter such as, for example, a BAW filter that includes one or more BAW resonators or a SAW filter that includes one or more SAW resonators). Acoustic elements can follow a fast phase response across the frequency of the filter elements of the duplexer34. Note that, in some embodiments, elements (e.g., acoustic elements) of the PRx filter48and/or the PTx filter58can be implemented on the same die (i.e., in a monolithic implementation of the duplexer34) or on separate dies .

The PTx filter58has a custom-shaped phase response in the feedback path. More specifically, in some embodiments, the PTx filter58has an amplitude and phase response that mimics that of the leakage path (i.e., the path through which the leakage signal propagates from the TX port38to the RX port44) across the TX band. In this manner, the PTx filter58compensates for the variation of the leakage signal across the TX band and, as a result, TX/RX isolation is improved.

The second leakage cancellation subsystem56also includes attenuation and phase adjustment circuitry62having an input coupled to the output of the PTx filter58and an output coupled to the RX port44of the duplexer34via a coupler64. The second leakage cancellation subsystem56operates to apply an attenuation, or amplitude offset, (A) and a phase shift, or phase offset, (φ) to a cancellation signal output by the PTx filter58. The amplitude offset (A) and the phase shift (φ) may, e.g., be dynamically (e.g., adaptively) configured or statically defined.

In operation, a TX signal is provided to the TX port38of the duplexer34. The TX signal is also provided to the PRx filter48via the coupler50and provided to the PTx filter58via the coupler60. The leakage cancellation subsystem46operates to mitigate, or cancel, the leakage signal within the RX band in such a manner as to account for variation in the amplitude and phase of the leakage signal across the RX band. Likewise, the second leakage cancellation subsystem56operates to mitigate, or cancel, the leakage signal within the TX band in such a manner as to account for variation in the amplitude and phase of the leakage signal across the TX band.

More specifically, the TX signal leaks from the TX port38through the TX filter36and the RX filter42to the RX port44of the duplexer34. The signal that leaks from the TX port38to the RX port44is the leakage signal. The details of the PRx filter48and the attenuation and phase adjustment circuitry52are described above and, as such, are not repeated. With respect to the second leakage cancellation subsystem56, the PTx filter58filters, or processes, the TX signal to thereby generate a cancellation signal having an amplitude and phase variation across the TX band that is a function of (e.g., mimics, e.g., is the same as or at least approximately the same as) the amplitude and phase variation of the leakage signal across the TX band. The attenuation and phase adjustment circuitry62applies the amplitude offset (A) and the phase shift (φ) to the cancellation signal to thereby provide an adjusted cancellation signal for the TX band. The amplitude offset (A) and the phase shift (φ) for the TX band are selected such that the adjusted cancellation signal for the TX band is 180° out-of-phase with (or approximately or very near 180° out-of-phase with) the leakage signal for the TX band and has the same (or approximately the same or very near the same) amplitude for the TX band. Note that the amplitude offset (A) and the phase shift (φ) for the TX band are preferably selected such that the phase offset between the adjusted cancellation signal for the TX band and the leakage signal for the TX band is as close to 180° as possible in the particular implementation and that the amplitude of the adjusted cancellation signal for the TX band is as close as possible to that of the leakage signal for the TX band in the particular implementation.

FIG. 9illustrates an embodiment of the system32that is similar to that ofFIG. 8but where the duplexer34is replaced with a multiplexer66. The embodiment ofFIG. 9demonstrates the concept as expanded on the multiplexer66. As an example, carrier aggregation cross-band isolation could be improved as well, with no fundamental effect on insertion losses (besides coupling traces). As illustrated, the multiplexer66includes a number of filters68-1through66-N including, in this example, M TX filters (where M≥2) that couple respective TX ports70to an antenna port72of the multiplexer66and at least one RX filter that each couples the antenna port72to a respective RX port74of the multiplexer66. In this example, two TX ports70-nand70-kare illustrated. The second leakage cancellation subsystem46operates to mitigate a leakage signal (in the RX band) from one TX port70-nto the RX port74taking into account a variation in the amplitude and phase of the leakage signal in the RX band, and the second leakage cancellation subsystem56operates to mitigate a leakage signal (in the TX band) from another TX port70-kto the RX port74taking into account the variation in the amplitude and phase of the leakage signal in the TX band.

More specifically, in this example, the input of the PRx filter48is coupled to the TX port70-nof the multiplexer66via the coupler50. The PRx filter48has an amplitude and phase response that mimics that of the leakage path (i.e., the path through which the leakage signal propagates from the TX port70-nto the RX port74) across the RX band. In this manner, the PRx filter48compensates for the variation of the leakage signal from the TX port70-nto the RX port74across the RX band and, as a result, TX/RX isolation is improved. Otherwise, the leakage cancellation subsystem46is the same as that described above.

In a similar manner, the input of the PTx filter58is coupled to the TX port70-kof the multiplexer66via the coupler60. The PTx filter58has an amplitude and phase response that mimics that of the leakage path (i.e., the path through which the leakage signal propagates from the TX port70-kto the RX port74) across the TX band. In this manner, the PTx filter58compensates for the variation of the leakage signal from the TX port70-kto the RX port74across the TX band. Otherwise, the second leakage cancellation subsystem56is the same as that described above. Note that while only two leakage cancellation subsystems46and56are illustrated inFIG. 9, the system32may include additional leakage cancellation systems.

FIG. 10illustrates an embodiment of the system32that is similar to that ofFIG. 9but where the second leakage cancellation subsystem56is replaced with a conventional leakage cancellation subsystem76. This embodiment demonstrates that a combination of the leakage cancellation subsystem46disclosed herein and the conventional approach is possible. While only one conventional leakage cancellation subsystem76is illustrated, one or more narrow bands could be cancelled out with one or more conventional leakage cancellation subsystems76. As illustrated and as discussed above, the conventional leakage cancellation subsystem76includes attenuation and phase adjustment circuitry78having an input coupled to, in this example, the TX port70-kof the multiplexer66via a coupler80and an output coupled to the RX port74via a coupler82. As described above, the conventional leakage cancellation subsystem76attenuates the leakage signal from the TX port70-nto the RX port74over a narrowband notch in the desired cancellation band (e.g., the TX band).

FIG. 11is a flow chart that illustrates a process for mitigating a leakage signal in a duplexer/multiplexer according to some embodiments of the present disclosure. As illustrated, the process includes generating a cancellation signal that is a function of (e.g., mimics) an amplitude variation and a phase variation of a leakage signal from a TX port to a RX port of a duplexer or multiplexer across a desired cancellation bandwidth, as described above (step100). The method further includes applying an amplitude offset and a phase offset to the cancellation signal to provide an adjusted cancellation signal, as described above (step102). The adjusted cancellation signal is applied to a RX signal output at the RX port of the duplexer or multiplexer to thereby mitigate the leakage signal, as described above (step104).