Various embodiments of the invention relate to a Multi-Band Voltage Controlled Oscillator (VCO). The multi-band VCO features a coupled-inductor based resonator. The resonator comprises a primary path and a secondary path inductively coupled to the primary path. The primary path comprises multiple LC tuning stages coupled in series with each stage having an adjustable capacitor and a primary inductor inductively coupled to the secondary path. The secondary path comprises multiple secondary inductors inductively coupled to respective primary inductors in the primary path. Furthermore, the secondary path comprises a plurality of controllable switches which are controlled to switch ON or OFF simultaneously to engage/disengage the inductive coupling between the primary path and the secondary path. Incorporating multiple LC tuning stages lowers voltage swing across each tuning stages, thus minimizing phase noise caused by nonlinearity in the resonator.

The invention relates to a radio frequency oscillator, the radio frequency oscillator comprising a resonator circuit being resonant at an excitation of the resonator circuit in a differential mode and at an excitation of the resonator circuit in a common mode, wherein the resonator circuit has a differential mode resonance frequency at the excitation in the differential mode, and wherein the resonator circuit has a common mode resonance frequency at the excitation in the common mode, a first excitation circuit being configured to excite the resonator circuit in the differential mode to obtain a differential mode oscillator signal oscillating at the differential mode resonance frequency, and a second excitation circuit being configured to excite the resonator circuit in the common mode to obtain a common mode oscillator signal oscillating at the common mode resonance frequency.

An element includes a coupling line in which a first conductor layer, a dielectric layer, and a second conductor layer are stacked in this order, and which is connected to the second conductor layer in order to mutually synchronize a plurality of antennas at a frequency of a terahertz wave; and a bias line connecting a power supply for supplying a bias signal to a semiconductor layer and the second conductor layer. A wiring layer in which the coupling line is formed and a wiring layer in which the bias line is formed are different layers. The bias line is disposed in a layer between the first conductor layer and the second conductor layer.

The invention relates to a resonator circuit, the resonator circuit comprising a transformer comprising a primary winding and a secondary winding, wherein the primary winding is inductively coupled with the secondary winding, a primary capacitor being connected to the primary winding, the primary capacitor and the primary winding forming a primary circuit, and a secondary capacitor being connected to the secondary winding, the secondary capacitor and the secondary winding forming a secondary circuit, wherein the resonator circuit has a common mode resonance frequency at an excitation of the primary circuit in a common mode, wherein the resonator circuit has a differential mode resonance frequency at an excitation of the primary circuit in a differential mode, and wherein the common mode resonance frequency is different from the differential mode resonance frequency.

The embodiments of the invention relate to a radio frequency oscillator, the radio frequency oscillator comprising a resonator circuit resonant at an excitation of the resonator circuit in a differential mode and at an excitation of the resonator circuit in a common mode, wherein the resonator circuit has a differential mode resonance frequency at the excitation in the differential mode, and wherein the resonator circuit has a common mode resonance frequency at the excitation in the common mode, a first excitation circuit configured to excite the resonator circuit in the differential mode to obtain a differential mode oscillator signal oscillating at the differential mode resonance frequency, and a second excitation circuit configured to excite the resonator circuit in the common mode to obtain a common mode oscillator signal oscillating at the common mode resonance frequency.

The invention relates to a resonator circuit, the resonator circuit comprising a transformer comprising a primary winding and a secondary winding, wherein the primary winding is inductively coupled with the secondary winding, a primary capacitor being connected to the primary winding, the primary capacitor and the primary winding forming a primary circuit, and a secondary capacitor being connected to the secondary winding, the secondary capacitor and the secondary winding forming a secondary circuit, wherein the resonator circuit has a common mode resonance frequency at an excitation of the primary circuit in a common mode, wherein the resonator circuit has a differential mode resonance frequency at an excitation of the primary circuit in a differential mode, and wherein the common mode resonance frequency is different from the differential mode resonance frequency.

A voltage controlled oscillator (VCO) and buffer circuit includes a voltage controlled oscillator (VCO), a buffer circuit configured to receive a signal generated by the VCO, the buffer circuit comprising a first transistor having a parasitic gate-source capacitance (Cgs), and a second transistor coupled across the first transistor, wherein a gate of the first transistor is coupled to a drain and a source of the second transistor, and a gate of the second transistor is coupled to a source of the first transistor.

Disclosed herein is a tunable resonant circuit including an inductance directly electrically connected in series between first and second nodes, a variable capacitance directly electrically connected between the first and second nodes, and a set of switched capacitances coupled between the first and second nodes. The set of switched capacitances includes a plurality of capacitance units, each capacitance unit comprising a first capacitance for that capacitance unit directly electrically connected between the first node and a switch and a second capacitance for the capacitance unit directly electrically connected between the switch and the second node. Control circuitry is configured to receive an input control signal and connected to control the switches of the set of switched capacitances. A biasing circuit is directly electrically connected to the tunable resonance circuit at the first and second nodes.

A method and circuit for linearizing a frequency response of an oscillator controlled by a plurality of capacitor banks are disclosed. In the disclosed method, for each capacitor bank of at least two capacitor banks of the oscillator, a respective sensitivity characteristic of the capacitor bank is determined. Further, a set of reference output frequency control words (FCWs) for an associated set of frequencies of the oscillator are determined. When an input FCW is received and an output FCW is responsively provided based on (i) an interpolation between two reference output FCWs of the set of reference output FCWs and (ii) the respective sensitivity characteristics of the at least two capacitor banks of the oscillator. The output FCW is then applied to the at least two capacitor banks of the oscillator.

A capacitor bank has a capacitance value that is discontinuous and has an extremely narrow variable range. Thus, in a case of obtaining a wide variable range of the capacitance value, a large number of capacitors are connected in parallel and used while being switched by switches. The present technology achieves at least one of: allowing the capacitance value of a variable capacitance circuit to be varied continuously by electrical control without increasing the parasitic capacitance; and decreasing the current consumption of an oscillator circuit using the variable capacitance circuit as compared to a conventional case. The variable capacitance circuit includes: a transconductance circuit that includes a MOS transistor; an inductor that is connected in parallel to the transconductance circuit; and a Gm control circuit that varies a transconductance of the MOS transistor.