Abstract: A circuit capable of automatically calibrating a resonant frequency of an antenna includes the antenna, a switch, a conversion unit, a count comparator, and a capacitor array. The switch is coupled to the antenna for being turned on and turned off according to a pulse. The antenna is used for generating the resonant frequency according to on and off of the switch. The conversion unit is coupled to the antenna for generating a clock according to a signal with the resonant frequency. The count comparator is coupled to the conversion unit for counting a number generated by a reference clock during a period of the clock, and comparing the pulse number with a predetermined value to generate an adjustment signal. The capacitor array is used for adjusting capacitance of the capacitor array according to the adjustment signal.

Abstract: A circuit for generating a direct current voltage includes a three-axis antenna set, a first capacitor, a limiting direct current voltage generator, a second capacitor, and a low dropout regulator. The three-axis antenna set receives a signal transmitted by a reader. The first capacitor generates a first direct current voltage according to an X-axis component, a Y-axis component, and a Z-axis component of the signal. The limiting direct current voltage generator limits and converts the X-axis component, the Y-axis component, and the Z-axis component to generate an X-axis direct current voltage, a Y-axis direct current voltage, and a Z-axis direct current voltage. The second capacitor generates a second direct current voltage according to the X-axis direct current voltage, the Y-axis direct current voltage, and the Z-axis direct current voltage. The low dropout regulator generates a direct current output voltage according to the second direct current voltage.

Abstract: An electronic oscillation signal generation circuit includes an electronic oscillation circuit, a DC voltage source for providing a DC voltage to the electronic oscillation circuit, a switch for electrically connecting the electronic oscillation circuit to ground when the switch is turned on so as to generate an analog oscillation signal after the switch is turned off, a conversion circuit for converting the analog oscillation signal to a digital oscillation signal, a counter for generating a control signal when the digital oscillation signal reaches a predetermined number of periods, a delay unit for generating a delay signal a predetermined time after a falling edge of the digital oscillation signal is triggered, and a pulse signal generation circuit electrically connected to the counter and the delay unit for generating a pulse signal according to the control signal and the delay signal so as to turn on the switch.

Abstract: An electronic oscillation signal generation circuit includes an electronic oscillation circuit, a DC voltage source for providing a DC voltage to the electronic oscillation circuit, a switch for electrically connecting the electronic oscillation circuit to ground when the switch is turned on so as to generate an analog oscillation signal after the switch is turned off, a conversion circuit for converting the analog oscillation signal to a digital oscillation signal, a counter for generating a control signal when the digital oscillation signal reaches a predetermined number of periods, a delay unit for generating a delay signal a predetermined time after a falling edge of the digital oscillation signal is triggered, and a pulse signal generation circuit electrically connected to the counter and the delay unit for generating a pulse signal according to the control signal and the delay signal so as to turn on the switch.

Abstract: A circuit for generating a direct current voltage includes a three-axis antenna set, a first capacitor, a limiting direct current voltage generator, a second capacitor, and a low dropout regulator. The three-axis antenna set receives a signal transmitted by a reader. The first capacitor generates a first direct current voltage according to an X-axis component, a Y-axis component, and a Z-axis component of the signal. The limiting direct current voltage generator limits and converts the X-axis component, the Y-axis component, and the Z-axis component to generate an X-axis direct current voltage, a Y-axis direct current voltage, and a Z-axis direct current voltage. The second capacitor generates a second direct current voltage according to the X-axis direct current voltage, the Y-axis direct current voltage, and the Z-axis direct current voltage. The low dropout regulator generates a direct current output voltage according to the second direct current voltage.

Abstract: A circuit capable of automatically calibrating a resonant frequency of an antenna includes the antenna, a switch, a conversion unit, a count comparator, and a capacitor array. The switch is coupled to the antenna for being turned on and turned off according to a pulse. The antenna is used for generating the resonant frequency according to on and off of the switch. The conversion unit is coupled to the antenna for generating a clock according to a signal with the resonant frequency. The count comparator is coupled to the conversion unit for counting a number generated by a reference clock during a period of the clock, and comparing the pulse number with a predetermined value to generate an adjustment signal. The capacitor array is used for adjusting capacitance of the capacitor array according to the adjustment signal.

Abstract: A gyrator includes a gyrator core and at least one common mode feedback circuit. The gyrator core includes four inverters mutually connected in a loop configuration between a pair of input ends and a pair of output ends. The common mode feedback circuit is provided between the pair of input ends and/or the pair of output ends and includes a forward-reverse connection inverter set and a backward-reverse connection inverter set. The forward-reverse connection inverter set has a first inverter, a second inverter connected in reverse series with the first inverter, and a first feedback resistor connected in parallel with the second inverter. The backward-reverse connection inverter set has a third inverter, a fourth inverter connected in reverse series with the third inverter, and a second feedback resistor connected in parallel with the fourth inverter.

Abstract: A gyrator includes a gyrator core and at least one common mode feedback circuit. The gyrator core includes four inverters mutually connected in a loop configuration between a pair of input ends and a pair of output ends. The common mode feedback circuit is provided between the pair of input ends and/or the pair of output ends and includes a forward-reverse connection inverter set and a backward-reverse connection inverter set. The forward-reverse connection inverter set has a first inverter, a second inverter connected in reverse series with the first inverter, and a first feedback resistor connected in parallel with the second inverter. The backward-reverse connection inverter set has a third inverter, a fourth inverter connected in reverse series with the third inverter, and a second feedback resistor connected in parallel with the fourth inverter.

Abstract: An antenna comprises a ground plate, a first plate, a connector, and a signal feeder having two terminals respectively electrically connected to the ground plate and the first plate. The first plate is set above the ground plate and comprises first, second, and third resonance regions with respective dimensions corresponding to wavelengths of first, second, and third frequencies at which the antenna operates. A connection region is connected to the first, second, and third resonance regions. The connector has two opposite ends respectively connected to the ground plate and the connection region. The first, second, and third frequencies respectively correspond to first, second, and third frequency bands of the antenna. The second frequency is close to the third frequency such that the second frequency band and the third frequency band are partially overlapped to cause the second frequency band and the third frequency band to merge.

Abstract: An antenna comprises a ground plate, a first plate, a connector, and a signal feeder having two terminals respectively electrically connected to the ground plate and the first plate. The first plate is set above the ground plate and comprises first, second, and third resonance regions with respective dimensions corresponding to wavelengths of first, second, and third frequencies at which the antenna operates. A connection region is connected to the first, second, and third resonance regions. The connector has two opposite ends respectively connected to the ground plate and the connection region. The first, second, and third frequencies respectively correspond to first, second, and third frequency bands of the antenna. The second frequency is close to the third frequency such that the second frequency band and the third frequency band are partially overlapped to cause the second frequency band and the third frequency band to merge.