# US 2021/0242859 A1 · Variable capacitance circuit and wireless communication device

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2021/0242859 A1
- Document ID: US20210242859A1
- Status: Published application
- Kind: A1
- Application number: 17/268,013
- Filed: 2019-07-17
- Published: 2021-08-05
- Earliest claimed: 2018-09-04
- Assignees: Sony Semiconductor Solutions Corporation
- Applicants: Sony Semiconductor Solutions Corporation
- Inventors: Hiroaki NAGANO
- Web page: https://patentgrep.com/patent/US20210242859A1

## CPC

- H03H 5/12: with at least one voltage- or current-dependent element
- H03H 11/28: Impedance matching networks
- H01Q 1/50: Structural association of antennas with earthing switches, lead-in devices or lightning protectors
- H03H 7/38: Impedance-matching networks
- H03K 17/6871: {the output circuit comprising more than one controlled field-effect transistor}
- H03K 17/6872: {using complementary field-effect transistors}
- H03K 17/6874: {in a symmetrical configuration}
- H10D 84/83138: {the IGFETs characterised by having different shapes or dimensions of their gate conductors}
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)
- H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72)
- H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

To achieve higher self-resonant frequency and lower parasitic resistance of a variable capacitance circuit whose capacitance value is changeable. The variable capacitance circuit includes a capacitor unit, a reactive element, and a bias circuit. The capacitor unit inside the variable capacitance circuit includes plural semiconductor elements connected in series, the plural semiconductor elements each having a capacitance value based on a bias voltage applied thereto. Further, the reactive element inside the variable capacitance circuit is connected to the capacitor unit. The bias circuit inside the variable capacitance circuit applies a bias voltage to each of the plural semiconductor elements.

## Claims

### Claim 1

A variable capacitance circuit comprising:
a capacitor unit including plural semiconductor elements connected in series, the plural semiconductor elements each having a capacitance value based on a bias voltage applied thereto;
a reactive element connected to the capacitor unit; and
a bias circuit configured to apply the bias voltage to each of the plural semiconductor elements.

### Claim 2 (depends on 1)

The variable capacitance circuit according to claim 1,
wherein the plural semiconductor elements include respective transistors, and
the bias circuit applies, as the bias voltage, any of an on voltage for turning on the transistors and an off voltage for turning off the transistors.

### Claim 3 (depends on 2)

The variable capacitance circuit according to claim 2,
wherein the off voltage includes plural voltages different from each other, and
the bias circuit applies any of the on voltage and the plural voltages as the bias voltage.

### Claim 4 (depends on 2)

The variable capacitance circuit according to claim 2,
wherein at least two of the transistors have different gate widths.

### Claim 5 (depends on 2)

The variable capacitance circuit according to claim 2,
wherein the transistors each include a transistor including a gate electrode with a linear shape.

### Claim 6 (depends on 1)

The variable capacitance circuit according to claim 1,
wherein the plural semiconductor elements each include a diode pair circuit including a pair of diodes having anodes connected to each other, and
the bias circuit applies any of a forward voltage and a backward voltage to the pair of diodes individually as the bias voltage.

### Claim 7 (depends on 1)

The variable capacitance circuit according to claim 1,
wherein plural array circuits connected in parallel are disposed in the capacitor unit, and
the plural semiconductor elements are disposed in each of the plural array circuits.

### Claim 8 (depends on 1)

The variable capacitance circuit according to claim 1,
wherein the reactive element is connected to the capacitor unit in series.

### Claim 9 (depends on 8)

The variable capacitance circuit according to claim 8,
wherein the reactive element includes an antenna radiator.

### Claim 10 (depends on 8)

The variable capacitance circuit according to claim 8,
wherein the capacitor unit is connected to each end of the reactive element.

### Claim 11 (depends on 1)

The variable capacitance circuit according to claim 1,
wherein the reactive element is connected to the capacitor unit in parallel.

### Claim 12

A wireless communication device comprising:
a capacitor unit including plural semiconductor elements connected in series, the plural semiconductor elements each having a capacitance value based on a bias voltage applied thereto;
a reactive element connected to the capacitor unit;
a bias circuit configured to apply the bias voltage to each of the plural semiconductor elements; and
an antenna radiator connected to at least one of the capacitor unit or the reactive element.