Linear Technology Corporation

Analog Devices International Unlimited Company

Linear Technology Holding LLC

William B Beckwith

Xudong Wang

Thomas E Schiltz

Michael W Bagwell

Miniature slow-wave transmission lines are described having an asymmetrical ground configuration. In some embodiments, the asymmetrical ground configuration facilitates a reduction in size. Non-uniform auxiliary conductors may be disposed above or below the co-planar waveguide to facilitate a reduction in the length of the miniature slow-wave transmission lines. Phase shifters may be implemented having a reduced size by including one or more miniature slow-wave transmission lines.

Miniature slow-wave transmission line with asymmetrical ground and associated phase shifter systems

An electrical circuit can be formed at least in part using lumped or discrete circuit elements to provide an artificial transmission line structure that can mimic the electrical properties of a corresponding actual transmission line structure. Such an artificial transmission line structure can generally consume less area than an actual transmission line structure lacking such lumped or discrete elements. Such an artificial transmission line structure can be formed using two or more 'unit cells' such as by cascading such cells as shown and described herein. The present inventors have recognized, among other things, that a unit cell of an artificial transmission line structure can include a t-coil section comprising magnetically-coupled inductors. Such an artificial transmission line structure can be used for applications such as phase shifting or to provide a delay line having a substantially constant group delay, among other applications.

Artificial transmission line using t-coil sections

An electronic circuit can include a gain adjustment circuit (e.g., a gain 'equalizer' circuit), such as to compensate for a variation in insertion loss over a specified range of frequencies. For example, such a gain adjustment circuit can provide an insertion loss characteristic having a specified slope. Such a slope can include a positive slope where insertion loss increases with respect to frequency, or a negative slope where insertion loss decreases with respect to frequency, as illustrative examples. A gain equalization technique can be used to compensate for variation in insertion loss versus frequency between different circuit paths, such as in relation to a switchable delay line having two or more selectable paths, such as for phase shifting applications. A gain adjustment circuit can be configured to provide relatively flat or constant time-domain delay versus frequency, such as inhibiting or reducing dispersion.

Delay compensation using broadband gain equalizer

A power divider/combiner circuit with coupled inductors is provided. With coupled inductors, the new circuit topology exhibits broader bandwidth for insertion loss, port matching and isolation compared with traditional power divider/combiner circuit topologies. The coupled inductors can be implemented for single-stage low-pass networks, multi-stage low-pass networks, or multi-stage wide-band networks. For example, the power divider/combiner circuit includes a first coupled inductor circuit coupled to an input terminal that provides a first signal path to a first output terminal, and a second coupled inductor circuit coupled to the input terminal that provides a second signal path to a second output terminal. Each of the coupled inductor circuits include multiple inductors that are tightly and positively magnetically coupled to one another. Each of the coupled inductor circuits provides an output signal that is based on a transfer function that includes a coupling coefficient of the corresponding coupled inductor circuit.

Wilkinson combiner with coupled inductors

A double-balanced FET mixer may include: single-ended RF port that receives or delivers single-ended RF signal; RF balun that converts the received single-ended RF signal into differential RF signal or generates delivered single-ended RF signal from received differential RF signal; local oscillator input port receives local oscillator signal; direct IF port receives or delivers an IF signal; and at least two FETs process the local oscillator signal and generate or process the differential RF signal and IF signal. The mixer may have no IF balun separate and distinct from tRF balun; may receive an input signal at RF port and generates output signal at IF port. The mixer may receive input signal at IF port and generate an output signal at the RF port, the output signal in either case being plus or minus the local oscillator signal. The double-balanced FET mixer may operate with IF frequencies down to DC.

Double-balanced field-effect transistor mixer with direct single-ended intermediate frequency outputs

A broadband radio frequency, microwave, or millimeter mixer system may include a balun and a mixer. The balun may have an unbalanced port; a balanced port; a first and a second inductor tightly and inversely magnetically coupled to one another; and a third inductor which is not magnetically coupled to the first or the second inductors. The mixer may be connected to the balanced port of the balun. The balun, including its three inductors, and the mixer may all be integrated onto a single substrate that forms an integrated circuit.

Broadband integrated RF/microwave/millimeter mixer with integrated balun(s)

Frequency conversion circuitry has an input node for receiving an input signal at a first frequency and an output node for producing an output signal at a second frequency different from the first frequency. A mixer circuit is responsive to the input signal for producing a signal at the second frequency. A step down impedance transformation circuit is coupled between the input node and an input of the mixer circuit for providing input impedance of the mixer circuit lower than impedance at the input node. An amplifier circuit is coupled between an output of the mixer circuit and the output node for amplifying the signal at the second frequency produced at the output of the mixer circuit. The mixer circuit is configured for providing input impedance of the output amplifier lower than the impedance at the input node.

Growing community of inventors

Larkspur, CO, United States of America

William B Beckwith