Aspects of methods and systems for high frequency signal selection are provided. The system for high frequency signal selection comprises a first driver and a second driver. The first driver is able to receive a first high frequency input, and the second driver is able to receive a second high frequency input. The output of the first driver is operably coupled, via a first inductive element, to a first resistive load and a first buffer, and the second driver is operably coupled, via a second inductive element, to the output of the first driver. One or both of the first high frequency input and the second high frequency input may be transferred to the first buffer by selectively enabling a current to one or both of the first driver and the second driver, respectively.

Aspects of methods and systems for high frequency signal selection are provided. The system for high frequency signal selection comprises a first driver and a second driver. The first driver is able to receive a first high frequency input, and the second driver is able to receive a second high frequency input. The output of the first driver is operably coupled, via a first inductive element, to a first resistive load and a first buffer, and the second driver is operably coupled, via a second inductive element, to the output of the first driver. One or both of the first high frequency input and the second high frequency input may be transferred to the first buffer by selectively enabling a current to one or both of the first driver and the second driver, respectively.

A dual-mode oscillator and a multi-phase oscillator includes a mode switching circuit to switch between two operating modes and obtain oscillation signals having two different bands. The dual-mode oscillator also includes two transformer-coupled oscillators and a step-up transformer in the transformer-coupled oscillators where the step-up transformer multiplies a drain voltage swing of a first MOS transistor and then injects a voltage signal to a gate of a second MOS transistor to obtain a larger gate voltage swing without increasing a supply voltage of the oscillator. The dual-mode oscillators are connected through multi-phase coupled circuits to form a Mobius loop.

A dual-mode oscillator and a multi-phase oscillator includes a mode switching circuit to switch between two operating modes and obtain oscillation signals having two different bands. The dual-mode oscillator also includes two transformer-coupled oscillators and a step-up transformer in the transformer-coupled oscillators where the step-up transformer multiplies a drain voltage swing of a first MOS transistor and then injects a voltage signal to a gate of a second MOS transistor to obtain a larger gate voltage swing without increasing a supply voltage of the oscillator. The dual-mode oscillators are connected through multi-phase coupled circuits to form a Mobius loop.

A buffer circuit includes a first MOSFET including a first source electrode, a first gate electrode, and a first drain electrode, and a second MOSFET, which includes a second source electrode, a second gate electrode, and a second drain electrode, and is same in polarity as the first MOSFET, and the first gate electrode and the second gate electrode are electrically connected to each other.

A buffer circuit includes a first MOSFET including a first source electrode, a first gate electrode, and a first drain electrode, and a second MOSFET, which includes a second source electrode, a second gate electrode, and a second drain electrode, and is same in polarity as the first MOSFET, and the first gate electrode and the second gate electrode are electrically connected to each other.

A microwave generator includes a power supply, an output circuit, a feedback oscillator, a pulse controller, a signal combination circuit and a semiconductor amplifier. The power supply converts input voltage and input current into output voltage and output current. The output circuit generates a microwave signal to an output terminal of the microwave generator and a feedback signal according to the microwave signal. The feedback oscillator generates an oscillation signal according to the feedback signal. According to a reference signal, the pulse controller generates a pulse signal. According to the oscillation signal and pulse signal, the signal combination circuit generates a control signal. The semiconductor amplifier generates and adjusts an amplified signal according to the control signal. The output circuit generates the microwave signal according to the amplified signal. The output current is adjusted according to the amplified signal. Consequently, the input current and the input voltage are in phase.

A microwave generator includes a power supply, an output circuit, a feedback oscillator, a pulse controller, a signal combination circuit and a semiconductor amplifier. The power supply converts input voltage and input current into output voltage and output current. The output circuit generates a microwave signal to an output terminal of the microwave generator and a feedback signal according to the microwave signal. The feedback oscillator generates an oscillation signal according to the feedback signal. According to a reference signal, the pulse controller generates a pulse signal. According to the oscillation signal and pulse signal, the signal combination circuit generates a control signal. The semiconductor amplifier generates and adjusts an amplified signal according to the control signal. The output circuit generates the microwave signal according to the amplified signal. The output current is adjusted according to the amplified signal. Consequently, the input current and the input voltage are in phase.

With respect to a phase locked loop (PLL) circuit that receives a first reference clock and generates an output clock, the PLL circuit includes a delay circuit that delays the first reference clock to generate a second reference clock, a feedback circuit that generates a control signal based on a phase difference between the second reference clock and a feedback clock, an oscillator that oscillates at a frequency determined based on the control signal to generate the output clock, and a divider that divides the output clock in the on state. The PLL circuit switches between a first mode and a second mode, the feedback clock in the first mode is a signal obtained by retiming an output of the divider with the output clock, and the feedback clock in the second mode is a signal obtained by retiming the first reference clock with the output clock.

An electronic circuit board includes a substrate having a multilayer structure including a ground layer, has at least one configuration in which, in a ground layer closest to a signal terminal of an oscillator, a region overlapping a signal terminal in a plan view is a non-forming region of a ground electrode, in a ground layer closest to a first wiring connecting the signal terminal of the oscillator and an input portion of an amplifier, a region overlapping the first wiring in the plan view is a non-forming region of a ground electrode, and in a ground layer closest to a second wiring connecting the signal terminal of the oscillator and an output portion of the amplifier, a region overlapping the second wiring in the plan view is a non-forming region of a ground electrode.