Integration of self-biased magnetic circulators with microwave devices is disclosed herein. In microwave and other high-frequency radio frequency (RF) applications, a magnetic circulator can be implemented with a smaller permanent magnet. Aspects disclosed herein include a process flow for producing a self-biased circulator in an integrated circuit chip. In this regard, a magnetic circulator junction can be fabricated on an active layer of a semiconductor wafer. A deep pocket or cavity is formed in an insulating substrate under the active layer. This cavity is then filled with a ferromagnetic material such that the circulator junction is self-biased within the integrated circuit chip, eliminating the need for an external magnet. The self-biased circulator provides high isolation between ports in a smaller integrated circuit.

Sequentially-Switched Delay Line (SSDL) can realize passive, nonmagnetic and non-reciprocal components for electromagnetic waves over ultra-wideband through the breaking of the time-reversal symmetry. A SSDL structure with six sections of transmission lines and five Single Pole Double Throw (SPDT) switches has been proposed as a three-port circulator in the literature. In this disclosure, a simpler structure consisting of only two sections of transmission lines with two switches is proposed, which can operate as a two-port non-reciprocal phase shifter (gyrator) with two SPDT switches, a three-port circulator with one DPDT switch and one SPDT switch, or a four-port circulator with two DPDT switches. Simulation results for one design at radio frequency demonstrated the expected non-reciprocal behavior from DC to 1.5 GHz for aforementioned three configurations.

Sequentially-Switched Delay Line (SSDL) can realize passive, nonmagnetic and non-reciprocal components for electromagnetic waves over ultra-wideband through the breaking of the time-reversal symmetry. A SSDL structure with six sections of transmission lines and five Single Pole Double Throw (SPDT) switches has been proposed as a three-port circulator in the literature. In this disclosure, a simpler structure consisting of only two sections of transmission lines with two switches is proposed, which can operate as a two-port non-reciprocal phase shifter (gyrator) with two SPDT switches, a three-port circulator with one DPDT switch and one SPDT switch, or a four-port circulator with two DPDT switches. Simulation results for one design at radio frequency demonstrated the expected non-reciprocal behavior from DC to 1.5 GHz for aforementioned three configurations.

An apparatus is disclosed having a circulator having a transmit port, a receive port, and a tuner port with tuner circuitry coupled between the tuner port and an antenna port. At least one analog control branch is coupled between the receive port and at least one control input of the tuner circuitry to generate at least one control signal from a transmit leakage signal leaking into the receive port. The tuner circuitry is configured to respond to the at least one control signal by automatically electronically tuning such that a cancellation signal of substantially equal amplitude and opposite phase of that of the transmit leakage signal is reflected through the tuner port and into the receive port, thereby reducing the transmit leakage signal to a level corresponding to an isolation of at least 30 dB between the transmit port and the receive port.

An apparatus is disclosed having a circulator having a transmit port, a receive port, and a tuner port with tuner circuitry coupled between the tuner port and an antenna port. At least one analog control branch is coupled between the receive port and at least one control input of the tuner circuitry to generate at least one control signal from a transmit leakage signal leaking into the receive port. The tuner circuitry is configured to respond to the at least one control signal by automatically electronically tuning such that a cancellation signal of substantially equal amplitude and opposite phase of that of the transmit leakage signal is reflected through the tuner port and into the receive port, thereby reducing the transmit leakage signal to a level corresponding to an isolation of at least 30 dB between the transmit port and the receive port.

A circulator is provided, comprising, first second and third conductors forming three equally spaced junctions and a permanent magnet configured to apply a shaped bias magnetic field to a ferrite resonator in operable communication with the first, second, and third conductors. The permanent magnet comprises a substantially planar monolithic structure having defined thereon at least first and second substantially concentric regions having first and second respective magnetic field strength levels, wherein the second magnetic field strength level is lower than the first magnetic field strength level. The first and second magnetic field strength levels are configured to cooperate to shape an external bias magnetic field of the permanent magnet to counteract at least a portion of a demagnetizing effect resulting from of an overall shape of the ferrite resonator, to achieve a substantially uniform internal magnetic bias within at least a portion of the ferrite resonator.

A circulator is provided, comprising, first second and third conductors forming three equally spaced junctions and a permanent magnet configured to apply a shaped bias magnetic field to a ferrite resonator in operable communication with the first, second, and third conductors. The permanent magnet comprises a substantially planar monolithic structure having defined thereon at least first and second substantially concentric regions having first and second respective magnetic field strength levels, wherein the second magnetic field strength level is lower than the first magnetic field strength level. The first and second magnetic field strength levels are configured to cooperate to shape an external bias magnetic field of the permanent magnet to counteract at least a portion of a demagnetizing effect resulting from of an overall shape of the ferrite resonator, to achieve a substantially uniform internal magnetic bias within at least a portion of the ferrite resonator.

Microwave circulators are an essentially component in many microwave systems and whilst the waveguide technologies they are implemented in have evolved their design today still employs procedures that are typically approximate and have no regular approach, which in many instances is through dependence on empirical equations or considered a trade secret that gives an edge to commercial suppliers of microwave and RF circulators. The result is expensive isolators where high performance is required as they are merely selected out or require manual tuning. Further, for broadband systems, designer's resort to dividing into sub-bands deploying multiple narrower band circulators. Accordingly, the inventors present a design methodology based on an accurate closed form solution allowing the selection of suitable ferrite specifications for the required operating bandwidth as well as calculating the ferrite disc impedance allowing the necessary matching network to be designed and the circulator design completed.

A circulator comprising a grounding plane including a first side and a second side, a magnet disposed on the first side of the grounding plane, a ferrite-based disk disposed on the second side of the grounding plane, and a conductor disposed on a side of the ferrite-based disk opposing the grounding plane. The conductor includes an elongate portion and the elongate portion has a distal end section projecting inwardly adjacent to a side of the magnet opposing the grounding plane. The circulator comprises a circulator housing including a plurality of side portions. The side portions have a first section and a second section, the second section extending further around a periphery of the housing than the first section such that a gap between neighboring first sections is wider than a gap between neighboring second sections.

A circulator comprising a grounding plane including a first side and a second side, a magnet disposed on the first side of the grounding plane, a ferrite-based disk disposed on the second side of the grounding plane, and a conductor disposed on a side of the ferrite-based disk opposing the grounding plane. The conductor includes an elongate portion and the elongate portion has a distal end section projecting inwardly adjacent to a side of the magnet opposing the grounding plane. The circulator comprises a circulator housing including a plurality of side portions. The side portions have a first section and a second section, the second section extending further around a periphery of the housing than the first section such that a gap between neighboring first sections is wider than a gap between neighboring second sections.