Transmission circuit
A transmission circuit includes: a plurality of impedance circuits having impedances different from each other, a plurality of first switch elements, any one of which is being connected to a respective one of the plurality of impedance circuits, and a first control circuit configured to control opening and closing of the plurality of first switch elements. The first control circuit is configured to be controllable to selectively change the opening and closing of the plurality of first switch elements and to rotate a reflection coefficient of an output terminal on an antenna side of the transmission circuit in a complex plane.
1 . A transmission circuit configured to be connected to an antenna, the transmission circuit comprising:
a plurality of impedance circuits having impedances different from each other; and
a plurality of first switch elements, any one of the plurality of first switch elements being connected to a respective one of the plurality of impedance circuits; and
a first control circuit configured to control opening and closing of the plurality of first switch elements, wherein
the first control circuit is configured to implement a single side band by selectively changing the opening and closing of the plurality of first switch elements and rotating a reflection coefficient of an output terminal on an antenna side of the transmission circuit in a complex plane to reduce an upper side band (USB) or a lower side band (LSB), the USB and LSB being frequency components offset from a carrier signal in a reflection signal transmitted by a wireless communication apparatus including the transmission circuit.
2 . The transmission circuit according to claim 1 , wherein
the plurality of impedance circuits comprises a plurality of inductor circuits configured to adjust inductance among reactance components of impedance.
3 . The transmission circuit according to claim 2 , wherein
the plurality of inductor circuits has impedances different from each other.
4 . The transmission circuit according to claim 2 , wherein
at least one of the plurality of inductor circuits comprises a plurality of inductor elements.
5 . The transmission circuit according to claim 2 , wherein
at least one of the plurality of inductor circuits comprises a resistive element.
6 . The transmission circuit according to claim 2 , wherein
at least one of the plurality of inductor circuits comprises a capacitor element.
7 . The transmission circuit according to claim 1 , wherein
the first control circuit is configured to be controllable to selectively change the opening and closing of the plurality of first switch elements and to rotate impedance at equal interval in the complex plane.
8 . The transmission circuit according to claim 1 , wherein
the plurality of impedance circuits comprises a plurality of capacitor circuits configured to adjust capacitance among reactance components of impedance.
9 . The transmission circuit according to claim 8 , wherein
the plurality of capacitor circuits has impedances different from each other.
10 . The transmission circuit according to claim 8 , wherein
at least one of the plurality of capacitor circuits comprises a plurality of capacitor elements.
11 . The transmission circuit according to claim 8 , wherein
at least one of the plurality of capacitor circuits comprises a resistive element.
12 . The transmission circuit according to claim 8 , wherein
at least one of the plurality of capacitor circuits comprises an inductor element.
13 . The transmission circuit according to claim 1 , wherein
the first control circuit is configured to be controllable to change impedance to rotate the reflection coefficient in the complex plane by controlling the plurality of first switch elements to close any one of the plurality of first switch elements.
14 . The transmission circuit according to claim 1 , wherein
the first control circuit is configured to be controllable to change impedance to rotate the reflection coefficient in the complex plane by controlling the plurality of first switch elements
to close any one of the plurality of first switch elements or
to open all of the plurality of first switch elements.
15 . The transmission circuit according to claim 1 , wherein
the first control circuit is configured to be controllable to rotate impedance in the complex plane by controlling the plurality of first switch elements
to close any one of the plurality of first switch elements,
to close at least two of the plurality of first switch elements, or
to open all of the plurality of first switch elements.
16 . The transmission circuit according to claim 1 , wherein
the first control circuit is configured to be controllable to rotate impedance in the complex plane by controlling the plurality of first switch elements
to close at least two of the plurality of first switch elements or
to open all of the plurality of first switch elements.
17 . The transmission circuit according to claim 1 , wherein
the transmission circuit comprises
a plurality of phase shifter circuits rotating a phase during transmission,
a plurality of second switch elements, any one of the plurality of second switch elements being connected to a respective one of the plurality of phase shifter circuits, and
a second control circuit configured to control opening and closing of the plurality of second switch elements, the second control circuit being configured to be controllable to change the opening and closing of the plurality of second switch elements, to change impedance, and to rotate a reflection coefficient with respect to the antenna in the complex plane.
18 . The transmission circuit according to claim 17 , wherein
the second control circuit is configured to be controllable to change impedance by closing any one of the plurality of second switch elements and to rotate the reflection coefficient with respect to the antenna in the complex plane.
19 . The transmission circuit according to claim 17 , wherein
the second control circuit is integrated with the first control circuit.