A wide-bandwidth resonant circuit is provided. In an embodiment disclosed herein, the wide-bandwidth resonant circuit includes a positive resonant circuit coupled in parallel to a negative resonant circuit. The positive resonant circuit and the negative resonant circuit can be configured to collectively exhibit certain impedance characteristics across a wide bandwidth. As a result, it is possible to utilize the wide-bandwidth resonant circuit to support a variety of wide-bandwidth applications, such as in a wide-bandwidth signal filter circuit.

An amplifier circuit according to the present invention includes a first block, a second block, a transformer, and a reference node and operates as a negative impedance converter circuit. A circuit configuration formed by a first transistor and at least one first passive component in the first block with respect to a first terminal of the transformer and a circuit configuration formed by a second transistor and at least one second passive component in the second block with respect to a second terminal of the transformer are the same as each other.

An amplifier circuit according to the present invention includes a first block, a second block, a transformer, and a reference node and operates as a negative impedance converter circuit. A circuit configuration formed by a first transistor and at least one first passive component in the first block with respect to a first terminal of the transformer and a circuit configuration formed by a second transistor and at least one second passive component in the second block with respect to a second terminal of the transformer are the same as each other.

A wide-bandwidth resonant circuit is provided. In an embodiment disclosed herein, the wide-bandwidth resonant circuit includes a positive resonant circuit coupled in parallel to a negative resonant circuit. The positive resonant circuit and the negative resonant circuit can be configured to collectively exhibit certain impedance characteristics across a wide bandwidth. As a result, it is possible to utilize the wide-bandwidth resonant circuit to support a variety of wide-bandwidth applications, such as in a wide-bandwidth signal filter circuit.

A wide-bandwidth resonant circuit is provided. In an embodiment disclosed herein, the wide-bandwidth resonant circuit includes a positive resonant circuit coupled in parallel to a negative resonant circuit. The positive resonant circuit and the negative resonant circuit can be configured to collectively exhibit certain impedance characteristics across a wide bandwidth. As a result, it is possible to utilize the wide-bandwidth resonant circuit to support a variety of wide-bandwidth applications, such as in a wide-bandwidth signal filter circuit.

The invention relates to a tunable, silicon-based negative-resistance circuit (10, 30) and to an active filter (50) for E-band frequencies (60 to 90 GHz). A base of a transistor (11) is connected to an on-chip inductive transmission line (13) which has a length of approximately a quarter-wavelength at a frequency of 83.5 GHz. The transmission line connects a DC voltage source (14) to the base terminal of the transistor (11) in order to bias the base. Another DC voltage source (15) is connected to the collector of the transistor (11) to bias the transistor. A capacitor (16) operatively bypasses or decouples the voltage source (15) in order to shunt high frequencies or alternating current (AC) signals to ground. The emitter terminal of the transistor (11) is connected to ground through a resistor (18) to limit the collector current (l.sub.e). The circuit gives rise to improved quality factor of resonators.

The invention relates to a tunable, silicon-based negative-resistance circuit (10, 30) and to an active filter (50) for E-band frequencies (60 to 90 GHz). A base of a transistor (11) is connected to an on-chip inductive transmission line (13) which has a length of approximately a quarter-wavelength at a frequency of 83.5 GHz. The transmission line connects a DC voltage source (14) to the base terminal of the transistor (11) in order to bias the base. Another DC voltage source (15) is connected to the collector of the transistor (11) to bias the transistor. A capacitor (16) operatively bypasses or decouples the voltage source (15) in order to shunt high frequencies or alternating current (AC) signals to ground. The emitter terminal of the transistor (11) is connected to ground through a resistor (18) to limit the collector current (l.sub.e). The circuit gives rise to improved quality factor of resonators.

The invention relates to a tunable, silicon-based negative-resistance circuit (10, 30) and to an active filter (50) for E-band frequencies (60 to 90 GHz). A base of a transistor (11) is connected to an on-chip inductive transmission line (13) which has a length of approximately a quarter-wavelength at a frequency of 83.5 GHz. The transmission line connects a DC voltage source (14) to the base terminal of the transistor (11) in order to bias the base. Another DC voltage source (15) is connected to the collector of the transistor (11) to bias the transistor. A capacitor (16) operatively bypasses or decouples the voltage source (15) in order to shunt high frequencies or alternating current (AC) signals to ground. The emitter terminal of the transistor (11) is connected to ground through a resistor (18) to limit the collector current (l.sub.e). The circuit gives rise to improved quality factor of resonators.

Reflectionless low-pass, high-pass, band-pass, band-stop, all-pass, all-stop, and multi-band filters, as well as a method for designing such filters is disclosed, along with a method of enhancing the performance of such filters through the use of unmatched sub-networks to realize an optimal frequency response, such as the Chebyshev equal-ripple response. These filters preferably function by absorbing the stop-band portion of the spectrum rather than reflecting it back to the source, which has significant advantages in many different applications. The unmatched sub-networks preferably offer additional degrees of freedom by which element values can be assigned to realize improved cutoff sharpness, stop-band rejection, or other measures of performance. The elements of the filter may be physical passive elements, or synthesized with active circuits, potentially realizing even negative element-values for improved performance.

Reflectionless low-pass, high-pass, band-pass, band-stop, all-pass, all-stop, and multi-band filters, as well as a method for designing such filters is disclosed, along with a method of enhancing the performance of such filters through the use of unmatched sub-networks to realize an optimal frequency response, such as the Chebyshev equal-ripple response. These filters preferably function by absorbing the stop-band portion of the spectrum rather than reflecting it back to the source, which has significant advantages in many different applications. The unmatched sub-networks preferably offer additional degrees of freedom by which element values can be assigned to realize improved cutoff sharpness, stop-band rejection, or other measures of performance. The elements of the filter may be physical passive elements, or synthesized with active circuits, potentially realizing even negative element-values for improved performance.