# US 10,483,643 B2 · Small antenna and calculation apparatus

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- Number: US 10,483,643 B2
- Document ID: US10483643B2
- Status: Granted
- Kind: B2
- Application number: 15/743,634
- Filed: 2016-06-16
- Published: 2018-07-12
- Granted: 2019-11-19
- Earliest claimed: 2015-07-31
- Assignees: Denso Corporation
- Applicants: Denso Corporation
- Inventors: Seishin Mikami
- Web page: https://patentgrep.com/patent/US10483643B2

## CPC

- H01Q 5/35: using two or more simultaneously fed points
- H01Q 5/357: using a single feed point
- H01Q 7/005: {with variable reactance for tuning the antenna}
- H01Q 9/28: Conical, cylindrical, cage, strip, gauze, or like elements having an extended radiating surface; Elements comprising two conical surfaces having collinear axes and adjacent apices and fed by two-conductor transmission lines (waveguide horns or mouths H01Q13/00; slot antennas H01Q13/00)
- H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72)

## Abstract

A small antenna includes: a first element having a pair of conductors with a power feeding point; and a second element as a conductor arranged to sandwich a dielectric body. A part of the first and second elements has an inductance shape. A first resonance mode with a same current direction of the first element as the second element has a first resonant frequency. A second resonance mode with an opposite current direction of the first element to the second element has a second resonant frequency. A length from each power feeding point to the inductance shape is determined to hold the first resonant frequency within a range from a frequency slightly higher than the second resonant frequency to a high anti-resonant frequency of the second resonance mode, or a range from a frequency slightly lower than the second resonant frequency to a low anti-resonant frequency of the resonance mode.

## Claims

### Claim 1

A small antenna comprising:
a first element that includes a pair of conductors provided by a wire, one end portion of each of the pair of conductors being a power feeding point; and
a second element that is arranged to face the first element with sandwiching a dielectric body, and includes a conductor provided by a wire, wherein:
a part of the wire of each of the first element and the second element has an inductance shape with three or more bending structures or an inductance shape with a spiral structure;
a first resonance mode, in which a current direction of current flowing through the first element is same as a current direction of current flowing through the second element, has a first resonant frequency (Fa0);
a second resonance mode, in which the current direction of current flowing through the first element is opposite to the current direction of current flowing through the second element, has a second resonant frequency (Fb0); and
a length from each power feeding point to the inductance shape is determined to hold the first resonant frequency of the first resonance mode within a range from a frequency slightly higher than the second resonant frequency of the second resonance mode to a high anti-resonant frequency of the second resonance mode, or a range from a frequency slightly lower than the second resonant frequency of the second resonance mode to a low anti-resonant frequency of the resonance mode.

### Claim 2 (depends on 1)

The small antenna according to claim 1, wherein:
the length from each power feeding point to the inductance shape is determined to hold the second resonant frequency of the second resonance mode within a range from a frequency slightly higher than the first resonant frequency of the first resonance mode to a high anti-resonant frequency of the first resonance mode, or a range from a frequency slightly lower than the first resonant frequency of the first resonance mode to a low anti-resonant frequency of the first resonance mode.

### Claim 3 (depends on 1)

The small antenna according to claim 1, wherein:
the frequency slightly higher than the second resonant frequency of the second resonance mode is defined as ((1+Δfm)/(1−Δfm))Fb0;
the frequency slightly higher than the second resonant frequency satisfies an equation of (1+Δfm)/(1−Δfm))Fb0<Fa0;
Δfm is a frequency ratio of a degradation range boundary;
Δfm is defined as an equation of Δfm=√(RaRbΔaΔb);
Ra is a resonance resistance value of the first resonance mode;
Rb is a resonance resistance value of the second resonance mode;
Δa is defined as an equation of Δa=(Δau+Δad)/2, Δa=Δau, or Δa=Δad;
Δau is defined as an equation of Δau=(Fau−Fa0)/Fa0;
Δau is a frequency ratio at which a reactance of the first resonance mode changes from 0 to 1;
Fau is a frequency at which the reactance of the first resonance mode is 1;
Fa0 is the first resonant frequency of the first resonance mode;
Δad is defined as an equation of Δad=(Fa0−Fad)/Fa0;
Δad is a frequency ratio at which the reactance of the first resonance mode changes from −1 to 0;
Fad is a frequency at which the reactance of the first resonance mode is −1,
Δb is defined as an equation of Δb=(Δbu+Δbd)/2, Δb=Δbu, or Δb=Δbd;
Δbu is defined as an equation of Δbu=(Fbu−Fb0)/Fb0;
Δbu is a frequency ratio at which a reactance of the second resonance mode changes from 0 to 1;
Fbu is a frequency at which the reactance of the second resonance mode is 1;
Fb0 is the second resonant frequency of the second resonance mode;
Δbd is defined as an equation of Δbd=(Fb0−Fbd)/Fb0;
Δbd is a frequency ratio at which the reactance of the second resonance mode changes from −1 to 0; and
Fbd is a frequency at which the reactance of the second resonance mode is −1; or
the frequency slightly lower than the second resonant frequency of the second resonance mode is defined as ((1−Δfm)/(1+Δfm))Fb0; and
the frequency slightly lower than the second resonant frequency satisfies an equation of ((1−Δfm)/(1+Δfm))Fb0>Fa0.

### Claim 4 (depends on 2)

The small antenna according to claim 2, wherein:
the frequency slightly higher than the first resonant frequency of the first resonance mode is defined as ((1+Δfm)/(1−Δfm))Fa0;
the frequency slightly higher than the first resonant frequency satisfies an equation of (1+Δfm)/(1−Δfm))Fa0<Fb0;
Δfm is a frequency ratio of a degradation range boundary;
Δfm is defined as an equation of Δfm=√(RaRbΔaΔb);
Ra is a resonance resistance value of the first resonance mode;
Rb is a resonance resistance value of the second resonance mode;
Δa is defined as an equation of Δa=(Δau+Δad)/2, Δa=Δau, or Δa=Δad;
Δau is defined as an equation of Δau=(Fau−Fa0)/Fa0;
Δau is a frequency ratio at which a reactance of the first resonance mode changes from 0 to 1;
Fau is a frequency at which the reactance of the first resonance mode is 1;
Fa0 is the first resonant frequency of the first resonance mode;
Δad is defined as an equation of Δad=(Fa0−Fad)/Fa0;
Δad is a frequency ratio at which the reactance of the first resonance mode changes from −1 to 0;
Fad is a frequency at which the reactance of the first resonance mode is −1,
Δb is defined as an equation of Δb=(Δbu+Δbd)/2, Δb=Δbu, or Δb=Δbd;
Δbu is defined as an equation of Δbu=(Fbu−Fb0)/Fb0;
Δbu is a frequency ratio at which a reactance of the second resonance mode changes from 0 to 1;
Fbu is a frequency at which the reactance of the second resonance mode is 1;
Fb0 is the second resonant frequency of the second resonance mode;
Δbd is defined as an equation of Δbd=(Fb0−Fbd)/Fb0;
Δbd is a frequency ratio at which the reactance of the second resonance mode changes from −1 to 0; and
Fbd is a frequency at which the reactance of the second resonance mode is −1, or
the frequency slightly lower than the first resonant frequency of the first resonance mode is defined as ((1−Δfm)/(1+Δfm))Fa0; and
the frequency slightly lower than the first resonant frequency satisfies an equation of ((1−Δfm)/(1+Δfm))Fa0>Fb0.

### Claim 5 (depends on 1)

The small antenna according to claim 1, wherein:
the first resonant frequency of the first resonance mode and the second resonant frequency of the second resonance mode are obtained by equations:
λa=Ca1*(Lm+S)+Ca0;
λb=Cb1*(Lm+S)+Cb0;
Fa0=C/λa; and
Fb0=C/λb,
where
Ca1 is a proportionality constant of λa,
Ca0 is a constant of λa,
Cb1 is a proportionality constant of λb,
Cb0 is a constant of λb; and
the length from each power feeding point to the inductance shape is determined that the first resonant frequency and the second resonant frequency satisfy an equation of:
((1+Δfm)/(1−Δfm))Fb0<Fa0<Fbru;
((1−Δfm)/(1+Δfm))Fb0>Fa0>Fbrd;
((1+Δfm)/(1−Δfm))Fa0<Fb0<Faru; or
((1−Δfm)/(1+Δfm))Fa0>Fb0>Fard,
where
Fard is a low anti-resonant frequency of the first resonance mode and the reactance is −∞,
Faru is a high anti-resonant frequency of the first resonance mode and the reactance is ∞,
Fbrd is a low anti-resonant frequency of the second resonance mode and the reactance is −∞, and
Fbru is a high anti-resonant frequency of the second resonance mode, and the reactance is ∞.

### Claim 6 (depends on 1)

The small antenna according to claim 1, wherein:
a width of at least a part of each wire other than the inductance shape is configured to be larger than a width of the inductance shape.

### Claim 7 (depends on 6)

The small antenna according to claim 6, wherein:
the width of each wire larger than the width of the inductance shape is set to bring an impedance of the first resonant frequency closer to a standard impedance.

### Claim 8 (depends on 1)

The small antenna according to claim 1, wherein:
the wire other than the power feeding point includes a short-circuit element that connects the first element and the second element.

### Claim 9 (depends on 1)

The small antenna according to claim 1, wherein:
the wire other than the inductance shape of the first element and the wire other than the inductance shape of the second element are bent.

### Claim 10 (depends on 1)

The small antenna according to claim 1, wherein:
the first element and the second element are arranged on a printed wiring board for providing a high frequency circuit.

### Claim 11 (depends on 10)

The small antenna according to claim 10, wherein:
another wire for connecting each power feeding point of the first element and an input and output terminal of the high frequency circuit is arranged on the printed wiring board.

### Claim 12 (depends on 1)

The small antenna according to claim 1, wherein:
the wide conductor of the first element is provided by a ground of the high frequency circuit.

### Claim 13 (depends on 1)

The small antenna according to claim 1, wherein:
the inductance shape with the three or more bending structures is a shape by aligning one or more semi-elliptical shapes.

### Claim 14 (depends on 1)

The small antenna according to claim 1, wherein:
the inductance shape with the three or more bending structures is a shape by aligning one or more triangles.

### Claim 15 (depends on 1)

The small antenna according to claim 1, wherein:
the inductance shape with the three or more bending structures is a shape by aligning one or more elliptical shapes.

### Claim 16 (depends on 1)

The small antenna according to claim 1, wherein:
the inductance shape with the three or more bending structures is a shape by aligning one or more square shapes.

### Claim 17 (depends on 1)

The small antenna according to claim 1, wherein:
the inductance shape with the spiral structure is a rectangular spiral structure.

### Claim 18 (depends on 1)

The small antenna according to claim 1, wherein:
the inductance shape with the spiral structure is an elliptical spiral structure.

### Claim 19 (depends on 1)

The small antenna according to claim 1, wherein:
the inductance shape disposed on each of the pair of conductors of the first element is different from each other.

### Claim 20 (depends on 1)

The small antenna according to claim 1, wherein:
a numerical number of various shapes in the inductance shape arranged on each of the pair of conductors of the first element and being a shape by aligning one or more various shapes is different from each other.

### Claim 21

A small antenna comprising:
a first element that includes a wire and a wide conductor; and
a second element that is arranged to face the wire of the first element with sandwiching a dielectric body, and includes a conductor provided by a wire, wherein:
a connecting portion between the wire of the first element and the wide conductor has a power feeding point, and an end portion of the second element has a power feeding point;
a part of the wire of each of the first element and the second element has an inductance shape with three or more bending structures or an inductance shape with a spiral structure;
a first resonance mode, in which a current direction of current flowing through the first element is same as a current direction of current flowing through the second element, has a first resonant frequency;
a second resonance mode, in which the current direction of current flowing through the first element is opposite to the current direction of current flowing through the second element, has a second resonant frequency; and
a length from each power feeding point to the inductance shape is determined to hold the first resonant frequency of the first resonance mode within a range from a frequency slightly higher than the second resonant frequency of the second resonance mode to a high anti-resonant frequency of the second resonance mode, or a range from a frequency slightly lower than the second resonant frequency of the second resonance mode to a low anti-resonant frequency of the second resonance mode.

### Claim 22

A calculation apparatus for designing a small antenna, which includes: a first element that has a pair of conductors provided by a wire, one end portion of each of the pair of conductors being a power feeding point; and a second element that is arranged to face the first element with sandwiching a dielectric body, and has a conductor provided by a wire, wherein:
a part of the wire of each of the first element and the second element has an inductance shape with three or more bending structures or an inductance shape with a spiral structure;
a first resonance mode, in which a current direction of current flowing through the first element is same as a current direction of current flowing through the second element, has a first resonant frequency;
a second resonance mode, in which the current direction of current flowing through the first element is opposite to the current direction of current flowing through the second element, has a second resonant frequency; and
the calculation apparatus receives the first resonant frequency and the second resonant frequency, and calculates one of an admittance, an impedance, a reflection coefficient, and a return loss of the small antenna.

### Claim 23 (depends on 22)

The calculation apparatus for antenna design according to claim 22, wherein:
the admittance is defined by equations of:
Yab=Ya+Yb;
Ya=1/Za;
Yb=1/Zb;
Za=Ra+jXa; and
Zb=Rb+jXb,
where Ra is a resonance resistance value of the first resonance mode,
Xa is a reactance value of the first resonance mode,
j is an imaginary number,
Rb is a resonance resistance value of the second resonance mode, and
Xb is a reactance value of the second resonance mode.

### Claim 24 (depends on 22)

The calculation apparatus for antenna design according to claim 22, wherein:
when an equation of Fa0≤F<Faru is satisfied, the reactance value of the first resonance mode is defined as an equation of Xa=Kau(1−(F/Fa0)2)/(1−(F/Faru)2),
where
F is a frequency for obtaining the impedance,
Faru is a high anti-resonant frequency of the first resonance mode and the reactance is ∞,
Fa0 is a first resonant frequency of the first resonance mode, and the reactance is 0, and
Kau is an upper proportionality constant of the first resonance mode;
when an equation of Fard <F≤Fa0 is satisfied, the reactance value of the first resonance mode is defined as an equation of Xa=Kad(1−(F/Fa0)2)/(1−(F/Fard)2),
where
Fard is a low anti-resonant frequency of the first resonance mode (A) and the reactance is −∞, and
Kad is a lower proportionality constant of the first resonance mode;
when an equation of Fb0≤F<Fbru is satisfied, the reactance value of the second resonance mode is defined as an equation of Xb=Kbu(1−(F/Fb0)2)/(1−(F/Fbru)2,
where
Fbru is a high anti-resonant frequency of the second resonance mode and the reactance is ∞,
Fb0 is a second resonant frequency of the second resonance mode and the reactance is 0, and
Kbu is an upper proportionality constant of the second resonance mode; and
when an equation of Fbrd <F≤Fb0 is satisfied, the reactance value of the second resonance mode is defined as an equation of Xb=Kbd(1−(F/Fb0)2)/(1−(F/Fbrd)2),
where
Fbrd is a low anti-resonant frequency of the second resonance mode and the reactance is −∞, and
Kbd is a lower proportionality constant of the second resonance mode.

### Claim 25

A calculation apparatus for designing a small antenna, which includes: a first element that has a wire and a wide conductor; and a second element that is arranged to face the wire of the first element with sandwiching a dielectric body, and has a conductor provided by a wire, a connecting portion between the wire of the first element and the wide conductor having a power feeding point, and an end portion of the second element having a power feeding point, wherein:
a part of the wire of each of the first element and the second element has an inductance shape with three or more bending structures or an inductance shape with a spiral structure;
a first resonance mode, in which a current direction of current flowing through the first element is same as a current direction of current flowing through the second element, has a first resonant frequency;
a second resonance mode, in which the current direction of current flowing through the first element is opposite to the current direction of current flowing through the second element, has a second resonant frequency; and
the calculation apparatus receives the first resonant frequency and the second resonant frequency, and calculates one of an admittance, an impedance, a reflection coefficient, and a return loss of the small antenna.

### Claim 26

A calculation apparatus for designing a small antenna, which includes: a first element that has a pair of conductors provided by a wire, one end portion of each of the pair of conductors being a power feeding point; and a second element that is arranged to face the first element with sandwiching a dielectric body, and has a conductor provided by a wire, wherein:
a part of the wire of each of the first element and the second element has an inductance shape with three or more bending structures or an inductance shape with a spiral structure; and
the calculation apparatus receives one resonant frequency of the first element and the second element, and calculates one of an other resonant frequency of the first element and the second element and an antenna shape.

### Claim 27 (depends on 26)

The calculation apparatus for antenna design according to claim 26, wherein:
when an equation of λ1=λa is satisfied, the other resonant frequency is calculated by:
(Lm+S)a=(λ1−Ca0)/Ca1;
λ2b=Cb1(Lm+S)a+Cb0; and
F2b=C/λ2b,
where
λ1 is a wavelength of the one resonant frequency and is defined as an equation of λ1=C/F1,
C is a speed of light,
F1 is the one resonant frequency,
λa is a wavelength at a resonance of the first resonance mode of the first element,
(Lm+S)a is a length of the first element up to the inductance shape,
Ca1 is a proportionality constant of λa,
Ca0 is a constant of λa,
Cb1 is a proportionality constant of λb,
Cb0 is a constant of λb,
λ2b is a wavelength of the other resonant frequency, and
F2b is the other resonant frequency;
when an equation of λ1=λb is satisfied, the other resonant frequency is calculated by:
(Lm+S)b=(λ1 −Cb0)/Cb1;
λ2a=Ca1(Lm+S)b+Ca0; and
F2a=C/λ2a,
where
λ1 is a wavelength of the one resonant frequency, and is defined as an equation of λ1=C/F1,
C is a speed of light,
F1 is the one resonant frequency,
λb is a wavelength at a resonance of the second resonance mode of the second element,
(Lm+S)b is a length of the second element up to the inductance shape,
Ca1 is a proportionality constant of λa
Ca0 is a constant of λa,
Cb1 is a proportionality constant of λb,
Cb0 is a constant of λb,
λ2a is a wavelength of the other resonant frequency, and
F2a is the other resonant frequency.

### Claim 28 (depends on 27)

The calculation apparatus for antenna design according to claim 27, wherein:
a numerical number of inductance shapes is defined as Ni, and Ni is a variable; and
the other resonant frequency or the antenna shape is calculated by replacing the proportionality constant of Ca1 of λa with the proportionality constant of Ca1(Ni) of λa, replacing the constant of Ca0 of λa with the constant of Ca0(Ni) of λa, replacing the proportional constant of Cb1 of λb with the proportionality constant of Cb1(Ni) of λb, and replacing the constant of Cb0 of λb with the constant of Cb0(Ni) of λb.

### Claim 29

A calculation apparatus for designing a small antenna, which includes: a first element that has a wire and a wide conductor; and a second element that is arranged to face the wire of the first element with sandwiching a dielectric body, and includes a conductor provided by a wire, a connecting portion between the wire of the first element and the wide conductor having a power feeding point, and an end portion of the second element having a power feeding point, wherein:
a part of the wire of each of the first element and the second element has an inductance shape with three or more bending structures or an inductance shape with a spiral structure; and
the calculation apparatus receives one resonant frequency of the first element and the second element, and calculates one of an other resonant frequency of the first element and the second element and an antenna shape.

### Claim 30

A small antenna comprising:
a first element that includes a pair of conductors provided by a wire, one end portion of each of the pair of conductors being a power feeding point; and
a second element that is arranged to face the first element with sandwiching a dielectric body, and includes a conductor provided by a wire, wherein:
a part of the wire of each of the first element and the second element has an inductance shape with three or more bending structures or an inductance shape with a spiral structure;
a length from a center of each of the first element and the second element to the inductance shape is determined to separate a first resonant frequency of a first resonance mode, in which a current direction of current flowing through the first element is same as a current direction of current flowing through the second element, from a second resonant frequency of a second resonance mode, in which the current direction of current flowing through the first element is opposite to the current direction of current flowing through the second element; and
a width of at least a part of each wire other than the inductance shape of the first element or the second element is configured to be wider than a width of the inductance shape.

### Claim 31 (depends on 30)

The small antenna according to claim 30, wherein:
a length from a center of each of the first element and the second element to the inductance shape is defined as (Lm+S);
the wavelength of the first resonant frequency is defined as λa; and
the wavelength of the second resonant frequency is defined as λb,
where
λa is defined as an equation of λa=Ca1*(Lm+S)+Ca0,
λb is defined as an equation of λb=Cb1*(Lm+S)+Cb0,
Ca1 is a proportionality constant of λa,
Ca0 is a constant of λa,
Cb1 is a proportionality constant of λb,
Cb0 is a constant of λb, and
the length (Lm+S) is set to satisfy an equation of λa≠λb.

### Claim 32 (depends on 31)

The small antenna according to claim 31, wherein:
the wire of the pair of conductors other than the feeding point includes a short-circuit element that connects the first element and the second element; and
a position of the short-circuit element is set to satisfy an equation of λa≠λb.

### Claim 33 (depends on 30)

The small antenna according to claim 30, wherein:
the width of each wire larger than the width of the inductance shape is set to bring an impedance of the first resonant frequency closer to a standard impedance.