JP2002299952A - Array antenna, its measuring method and method for measuring antenna device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an array antenna device which suppresses nonlinear distortion such as the second higher harmonic wave distortion, etc., and can operate even large signal power. SOLUTION: This array antenna device 100a is provided with a driven element A10 for transmitting and receiving a radio signal, a plurality of balanced nondrive elements 13a to 13b disposed away from the driven element A10 only by a prescribed interval, and a plurality of variable reactance circuits respectively connected to a plurality of balanced nondrive elements 13a to 13b, respectively operates the plurality of balanced nondrive elements 13a to 13b as a wave guide or a reflector by changing the reactance of each of the variable reactance circuits and changes the directivity of an array antenna. Here, each variable reactance circuit is provided with variable capacitive diodes 14a to 14d being at least one pair of variable reactance elements connected backwardly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an array antenna device having a plurality of antenna elements capable of changing the directional characteristics thereof, a method of measuring the same, and an antenna device having at least one antenna element. Regarding the measuring method, in particular, an electronically controlled waveguide array antenna device (Electronically Steerable Passive Array R)
adiator (ESPAR) Antenna; hereinafter, referred to as ESPAR antenna. ) And its measurement method.

[0002]

2. Description of the Related Art The basic configuration of a conventional ESPAR antenna is described in, for example, the prior art document 1 "T. Ohira et al.," Elect.
ronically steerable passive array radiator antenna
s for low-cost analog adaptive beamforming, "2000
IEEE International Conferenceon Phased Array Syste
m & Technology pp. 101-104, Dana point, Californi
a, May 21-25, 2000 "and JP-A-2001-024431. This ESPAR antenna is
An excitation element to which a radio signal is supplied, at least one non-excitation element provided at a predetermined distance from the excitation element and not supplied with a radio signal, and a variable reactance element connected to the non-excitation element. The directional characteristics of the array antenna can be changed by changing the reactance value of the variable reactance element.

FIG. 18 shows, for example, Japanese Patent Application No. 2000-307.
FIG. 1 is a block diagram illustrating a configuration of a conventional array antenna control device including an adaptive control type controller 20 disclosed in the patent application No. 548.
As shown in FIG. 18, the control device for the array antenna includes a conventional ESPAR antenna including one excitation element A0, six non-excitation elements A1 to A6, and a ground conductor 11. It comprises an array antenna device 100, an adaptive control type controller 20, a learning sequence signal generator 21, a high frequency receiver 22, and a demodulator 23. In the example of FIG. 18, each of the non-exciting elements A1 to A6 is of a monopole type, but as shown in FIG. 19, a variable reactance element 12 is inserted between a pair of antenna elements 13a and 13b. A dipole type parasitic element A10, which is a so-called balanced type parasitic element, may be used.
The variable capacitance diode 14 shown in FIG. Each of the elements A0 to A6 is a monopole antenna element having a length of, for example, λ / 4 (where λ is a wavelength).

Here, the adaptive control type controller 20 comprises:
For example, a digital computer such as a computer is used. Before starting the wireless communication by the demodulator 23, the learning sequence signal included in the wireless signal transmitted from the transmitter at the other end is excited by the excitation element A of the array antenna apparatus 100.
0 based on the received signal y (t) when received by 0 and the learning sequence signal r (t) which is the same as the learning sequence signal and is generated by the learning sequence signal generator 21. By executing, the reactance value x _m (m = m = _m) of each of the variable reactance elements A1 to A6 for directing the main beam of the array antenna apparatus 100 in the direction of the desired wave and directing null in the direction of the interference wave.
1, 2, ..., 6) are calculated and set.

In FIG. 18, a radio signal transmitted from a partner transmitter is received by an array antenna device 100, and a signal output from an excitation element A0 is a low-noise amplifier, an intermediate frequency or a baseband signal. The received signal y (t) is transmitted via the high-frequency receiving unit 22 that performs processing such as frequency conversion.
Is transmitted to the adaptive control type controller 20 and the demodulator 23. The adaptive control type controller 20 executes the above-described adaptive control processing to execute the array antenna control device 10.
After adaptively controlling the main beam of “0” in the direction of the desired wave and nulling in the direction of the interference wave, the wireless communication by the demodulator 23 is started. Here, the demodulator 23 performs a process such as demodulation on the received signal y (t) to obtain and output a demodulated signal.

In the array antenna apparatus 100 shown in FIG. 18, an excitation element A0 and six non-excitation elements A1 to A6 are provided.
Are electrically insulated from the ground conductor 11 formed of a conductor plate having a sufficiently large width with respect to the length of each of the elements A0 to A6, and have, for example, a radius d = λ around the excitation element A0. 60 identical to each other at the position of the circular shape of / 4
The non-exciting elements A1 to A6 are provided so as to be arranged at intervals of degrees. Here, the array antenna device 100 is a reversible circuit, and when used as a transmission antenna, a radio signal is supplied only to the excitation element A0, while when used as a reception antenna, a radio signal from a partner transmitter is used. The signal is received by the excitation element A0 as a received signal y (t).

[0007]

When the ESPAR antenna of the prior art shown in FIG. 18 is used with a relatively large transmission power of, for example, 1 W or more, there are the following problems.
That is, one variable capacitance diode 14 is used as the variable reactance element 12 loaded on the non-excitation elements A1 to A6.
However, the junction capacitance of the variable capacitance diode 14 changes according to the DC bias voltage applied to both ends, and the junction capacitance of the variable capacitance diode 14 also changes according to the high frequency voltage of the radio signal applied to both ends. Resulting in. The calculation for the high-frequency current i flowing through the parasitic elements A1 to A6 in this case is as follows.

Now, the junction capacitance C of the variable capacitance diode 14 is changed by a high-frequency voltage V = a · cos applied to both ends thereof.
It is expressed by the following equation using ωt.

## EQU1 ## C = C ₀ + C ₁ V

Here, C ₀ and C ₁ are constants determined by the applied voltage versus junction capacitance characteristics. At this time, the high-frequency current i flowing through the variable capacitance diode 14 is expressed by the following equation.

[0010]

(Equation 2)

(Equation 3)

As shown in the second term on the right-hand side of the final equation of Equation 3, there is a problem that nonlinear distortion such as second harmonic distortion occurs.

Conventionally, it has not been possible to measure a high-frequency current flowing through an antenna device having at least one antenna element or an antenna element of an array antenna device such as the above-mentioned ESPAR antenna. Wave distortion, non-linear distortion such as third harmonic distortion, or intermodulation distortion could not be measured.

An object of the present invention is to solve the above problems and to provide an array antenna device capable of suppressing nonlinear distortion such as second harmonic distortion and operating with a large signal power.

Another object of the present invention is to solve the above-mentioned problems, and to provide a high-frequency current flowing through a parasitic element of an array antenna device such as an ESPAR antenna, a second harmonic distortion, or a third harmonic distortion. It is an object of the present invention to provide a method for measuring an array antenna device capable of measuring non-linear distortion and intermodulation distortion.

Another object of the present invention is to solve the above problems and to provide a method of measuring an antenna device capable of measuring a high-frequency current flowing through an antenna element of an antenna device having at least one antenna element. It is in.

[0016]

According to a first aspect of the present invention, there is provided an array antenna apparatus comprising: an excitation element for transmitting and receiving a radio signal; and a plurality of balanced non-excitation elements provided at a predetermined distance from the excitation element. And a plurality of variable reactance circuits respectively connected to the plurality of balanced non-exciting elements. By changing reactance values of the respective variable reactance circuits, the plurality of balanced non-exciting elements are respectively induced. In an array antenna device that operates as a wave reflector or a reflector and changes the directional characteristics of the array antenna, each of the variable reactance circuits includes at least one pair of variable reactance elements connected in opposite directions. I do.

In the above array antenna device, each of the variable reactance circuits is preferably such that at least one pair of circuit groups in which each circuit group includes a plurality of variable reactance elements connected in parallel is connected in opposite directions. It is characterized by having been constituted.

In the above array antenna device,
Preferably, each of the variable reactance circuits is configured such that at least one pair of circuit groups, each of which includes a plurality of variable reactance elements connected in series and in parallel, is connected in opposite directions. It is characterized by.

Further, in the above array antenna device, each of the variable reactance elements is preferably made of a variable capacitance diode having substantially the same applied voltage-to-junction capacitance characteristic.

Still further, in the above array antenna device, preferably, a dielectric film is provided around the excitation element, and the plurality of balanced non-excitation elements are formed on the dielectric film.

According to a second aspect of the present invention, there is provided a method for measuring an array antenna device, comprising the steps of: accommodating the array antenna device in a non-reflective radio wave environment; Supplying power and providing a magnetic field detecting means in close proximity to one of the plurality of balanced non-exciting elements so as not to contact the one; and detecting a magnetic field of the balanced non-exciting element to thereby provide the balanced non-exciting element. Detecting a high-frequency current of the element.

According to a third aspect of the present invention, there is provided a method for measuring an array antenna device, comprising the steps of: accommodating the array antenna device in a non-reflective radio wave environment; A step of supplying a high-frequency signal; and providing a magnetic field detecting means in proximity to one of the plurality of balanced non-exciting elements so as not to contact the same; And detecting a signal level of at least one of a fundamental wave and a harmonic based on the detected high-frequency current.

According to a fourth aspect of the present invention, there is provided a method for measuring an array antenna device according to the fourth aspect of the present invention, wherein the step of housing the array antenna device in a non-reflective radio wave environment, and the step of: Supplying high frequency signals of at least two fundamental waves,
Providing a magnetic field detecting means in close proximity to one of the plurality of balanced non-exciting elements so as not to contact the same, and detecting a high-frequency current by detecting a magnetic field of the balanced non-exciting element; Detecting a signal level of at least one of a fundamental wave and a harmonic based on the obtained high-frequency current.

According to a fifth aspect of the present invention, there is provided a method of measuring an antenna device having at least one antenna element, wherein the step of housing the antenna device in a non-reflective radio wave environment includes the steps of: Feeding a high-frequency signal to the antenna element, and providing a magnetic field detecting means close to the antenna element so as not to contact the antenna element, and detecting a high-frequency current of the antenna element by detecting a magnetic field of the antenna element. It is characterized by.

[0025]

Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment> FIG. 1 shows a first embodiment according to the present invention. For example, a so-called balanced non-exciting element used in the array antenna apparatus 100 shown in FIG. It is a circuit diagram which shows the structure of A11. In this embodiment, each variable reactance element 12 used for each of the parasitic elements A1 to A6 in FIG.
Is characterized in that each of the variable capacitance diodes 14a and 14b has substantially the same applied voltage-variable capacitance characteristics, and includes a pair of variable capacitance diodes 14a and 14b connected in opposite directions.

In the dipole type parasitic element A11 shown in FIG. 1, for example, the antenna element 13 having a length of λ / 4 is used.
a is connected to the cathode of the variable capacitance diode 14a, and connected to the controller 20 via a resistor 15a.
DC bias application terminal Vc-. The anode of the variable capacitance diode 14a is connected to the DC bias application terminal Vc- of the controller 20 via the resistor 15c. On the other hand, one end of the other antenna element 13b (located on the side of the antenna element 13a) is connected to the cathode of the variable capacitance diode 14b, and the DC bias application terminal Vc + of the controller 20 via the resistor 15b.
Connected to. The anode of the variable capacitance diode 14b is connected to the DC bias application terminal Vc- of the controller 20 via the resistor 15c. Here, the DC bias application terminals Vc + and Vc− of the controller 20 are shown in FIG.
8 is a terminal for outputting a reactance value signal.

The array antenna device 100 shown in FIG.
When all the parasitic elements A1 to A6 in FIG. 1 use the dipole parasitic element A11 in FIG.
Is not necessary, and the excitation element A0 may be a monopole excitation element or a dipole excitation element. Further, the variable capacitance diodes 14a and 14b of each of the non-excited elements A1 to A6 have substantially the same applied voltage-to-junction capacitance characteristics, and have the characteristics expressed by the above equation (1).

[0029] In the array antenna apparatus arranged as described above, the high frequency current i _a flowing through the upper side of the variable capacitance diode 14a of Figure 1, like the number 3 above is expressed by the following equation.

[0030]

Equation 4] _{i a = -C 0 aωsinωt-C} 1 a 2 ωsin2ωt

Further, the lower variable capacitance diode 1 shown in FIG.
Since the DC bias voltage is applied in the reverse direction, the junction capacitance 4b is expressed by the following equation.

[0032]

## EQU5 ## C = C ₀ −C ₁ V

Therefore, the lower variable capacitance diode 14b
Frequency current i _b flowing in is expressed by the following equation.

[0034]

[6] _{i b = -C 0 aωsinωt + C} 1 a 2 ωsin2ωt

Therefore, the high-frequency current i flowing through the entire non-exciting element A11 is expressed by the following equation.

[0036]

Equation 7] _{i = i a + i b =} -C 0 aωsinωt-C 1 a 2 ωsin2ωt -C 0 aωsinωt + C 1 a 2 ωsin2ωt = 2C 0 aωsinωt

As is apparent from the above equation (7), the fundamental (ω) components flowing through the two variable capacitance diodes 14a and 14b remain in the same phase, but the second harmonic (2ω) component has the opposite phase. As a result, the second harmonic component is suppressed.

As described above, according to the present embodiment, each of the variable capacitance diodes 14a, 1 is used as each of the variable reactance elements 12 used for each of the parasitic elements A1 to A6.
4b have substantially the same applied voltage versus variable capacitance characteristics;
A pair of variable capacitance diodes 1 connected in opposite directions
Since 4a and 14b are used, nonlinear distortion such as second harmonic distortion can be suppressed.

<Second Embodiment> FIG. 2 shows a second embodiment according to the present invention, which is used in an array antenna device.
FIG. 9 is a circuit diagram showing a configuration of a dipole-type parasitic element A12 called a so-called balanced parasitic element. In this embodiment, each of the circuit groups 61 and 6 is used as the variable reactance element 12 used for each of the parasitic elements A1 to A6 in FIG.
2 is two variable capacitance diodes 14a, 14c or 14
It is characterized in that at least one pair of circuit groups 61 and 62 composed of circuits b and 14d connected in parallel are connected in opposite directions. Each of the variable capacitance diodes 14a, 14b, 14c, 14d has substantially the same applied voltage to junction capacitance characteristics.

In the dipole type parasitic element A12 of FIG. 2, one end of the antenna element 13a is connected to each cathode of two variable capacitance diodes 14a and 14c, and a DC bias application terminal of the controller 20 via the resistor 15a. Vc-. Each anode of the two variable capacitance diodes 14a and 14c is connected to a resistor 15c.
Through the DC bias application terminal Vc of the controller 20
Connected to-. These two variable capacitance diodes 14
a and 14c constitute a circuit group 61. On the other hand, one end (located on the side of the antenna element 13a) of the other antenna element 13b is connected to two variable capacitance diodes 14b, 14b.
d, and connected to the DC bias application terminal Vc + of the controller 20 via the resistor 15b. Further, two variable capacitance diodes 14b,
Each anode 14d is connected to a DC bias application terminal Vc- of the controller 20 via a resistor 15c. A circuit group 62 is configured by these two variable capacitance diodes 14b and 14d.

As described above, according to the present embodiment, as the variable reactance element 12 used for each of the parasitic elements A1 to A6 in FIG. 18, each of the circuit groups 61 and 62 includes two variable capacitance diodes 14a and 14c or 14b, 14
Since at least one pair of circuit groups 61 and 62 composed of circuits connected in parallel with each other are connected in opposite directions to each other, non-linear signals such as second harmonic distortion are formed as in the first embodiment. Distortion can be suppressed. Further, each circuit group 61,
Since the variable capacitance diodes are connected in parallel at 62, it is possible to provide a high power array antenna device that can withstand a large current.

In the above embodiment, the anodes of the variable capacitance diodes 14a, 14b, 14c, 14d are connected to each other. However, the present invention is not limited to this, and at least the anode of the variable capacitance diode 14a, The anode of the variable capacitance diode 14b is connected, and the connection point is connected to the DC bias application terminal Vc− of the controller 20 via the resistor 15c, while the anode of the variable capacitance diode 14b and the anode of the variable capacitance diode 14d are connected. Is connected to another resistor 15d.
(Not shown) may be connected to the DC bias application terminal Vc- of the controller 20.

<Third Embodiment> FIG. 3 shows a third embodiment according to the present invention, which is used in an array antenna device.
FIG. 4 is a circuit diagram showing a configuration of a dipole-type parasitic element A13 called a so-called balanced parasitic element. In this embodiment, as the variable reactance element 12 used for each of the parasitic elements A1 to A6 in FIG.
It is characterized in that at least one pair of circuit groups 71 and 72 composed of circuits in which the variable capacitance diodes 31-34 or 41-44 are connected in series and in parallel are connected in opposite directions. . Each of the variable capacitance diodes 31-34 and 41-44 has substantially the same applied voltage to junction capacitance characteristics.

In the dipole parasitic element A13 shown in FIG. 3, two variable capacitance diodes (31, 32),
(33, 34), (41, 42) and (43, 44) are connected in series in the same direction. Here, one end of the antenna element 13a is connected to two variable capacitance diodes 3
1 and 33, and a resistor 15
a, the DC bias application terminal V of the controller 20
c-. Also, two variable capacitance diodes 4
Each of the anodes 1 and 43 is connected to the DC bias application terminal Vc- of the controller 20 via the resistor 15c. The circuit group 71 is constituted by the four variable capacitance diodes 31-34. On the other hand, the other antenna element 13
One end of b (located on the antenna element 13a side) is connected to each cathode of the two variable capacitance diodes 41 and 43, and is connected to the DC bias application terminal Vc + of the controller 20 via the resistor 15b. Each anode of the two variable capacitance diodes 42 and 44 is connected to a resistor 15
c, the DC bias application terminal V of the controller 20
c-. A circuit group 72 is constituted by the four variable capacitance diodes 41-44.

As described above, according to the present embodiment, each of the circuit groups 71 and 72 includes four variable capacitance diodes 31 to 34 as the variable reactance element 12 used for each of the parasitic elements A1 to A6 in FIG. Or, since at least one pair of circuit groups 71 and 72 composed of circuits in which 41-44 are connected in series and in parallel are connected in opposite directions, the same as in the first and second embodiments. In addition, non-linear distortion such as second harmonic distortion can be suppressed. Also,
Since the variable capacitance diodes are connected in series and in parallel in each of the circuit groups 71 and 72, it is possible to provide an array antenna device for high power that can withstand a large current and a high voltage.

In the above embodiment, the respective anodes of the variable capacitance diodes 32, 34, 42, and 44 are connected to each other. However, the present invention is not limited to this. The anode of the variable capacitance diode 42 is connected, and the connection point is connected to the DC bias application terminal Vc− of the controller 20 via the resistor 15c, while the anode of the variable capacitance diode 34 and the anode of the variable capacitance diode 44 are connected. And the connection point is connected to the DC bias application terminal Vc- of the controller 20 via another resistor 15d (not shown).
May be connected.

A connection point 51 between the variable capacitance diode 31 and the variable capacitance diode 32 and a connection point 51 between the variable capacitance diode 33 and the variable capacitance diode 34 are connected to each other. 42 and a variable capacitance diode 43
The connection point 54 between the variable capacitance diode 44 and the variable capacitance diode 44 may be connected to each other.

In the third embodiment, each circuit group 71
Or 72, four variable capacitance diodes are used. However, the present invention is not limited to this, and includes four or more variable capacitance diodes, and the lower circuit group 71 and the upper circuit group 72 Each circuit may be configured to have the same circuit configuration.

<Fourth Embodiment> FIG. 4 is a fourth embodiment according to the present invention and is a perspective view showing a configuration of an array antenna device used in an experimental example, and a variable reactance element circuit used in the array antenna device. FIG. 4A is a circuit diagram showing a configuration, and FIG. 4A shows a single varactor type (SV) according to a conventional example
FIG. 4 is a circuit diagram showing a variable reactance element circuit of FIG.
(B) is an anti-series varactor type (ASVP) according to the embodiment.
FIG. 3 is a circuit diagram showing a variable reactance element circuit of FIG.

The array antenna device according to this embodiment is an ESPAR antenna device 100a, in which an excitation element A
10 uses a sleeve antenna, and its excitation element A1
A cylindrical dielectric film 80 made of, for example, flexible polyimide or Teflon (registered trademark) is provided so as to surround 0 at equal intervals (that is, located on the axis of the cylinder). Antenna elements 13a and 13b of each parasitic element are positioned at an angle of 60 degrees with respect to the cylindrical axis, and
It is formed by a printed wiring method so that the longitudinal directions of a and 13b are parallel to the cylindrical axis. In addition, the outer periphery of the dielectric film 80 is covered with a transparent plastic layer (not shown) for protection. In order not to affect the radiation of the ESPAR antenna device 100a, the antenna elements 13a, 13b
The overlying plastic layer has been removed.

Further, the antenna element 13 of each parasitic element
A variable reactance circuit is provided on the dielectric film 80 at the center of each excitation element where a and 13b are close to each other. In the conventional example of FIG. 4A, a single varactor (SV) variable reactance circuit having one variable capacitance diode 14 is provided. Here, one end of the antenna element 13a is connected to the cathode of the variable capacitance diode 14, and the bias voltage V
_connected to a direct current bias power supply (not shown) having a _cont . One end of the antenna element 13b is connected to the anode of the variable capacitance diode 14, and the resistance 1
7b is grounded.

On the other hand, in the embodiment of FIG. 4B, an anti-series varactor type (ASVP) variable reactance circuit having four variable capacitance diodes 14a, 14b, 14c and 14d is provided. Here, one end of the antenna element 13a is connected to each anode of the variable capacitance diodes 14a and 14b, and is grounded via a resistor 17c. On the other hand, one end of the antenna element 13b is
4c and 14d are connected to the respective anodes and grounded via a resistor 17b. Further, the respective cathodes of the variable capacitance diodes 14a, 14b, 14c, 14d are connected together, and the bias voltage V
_connected to a direct current bias power supply (not shown) having a _cont .

[0053]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As described in the section of the prior art, one of the problems to be solved in putting an ESPAR antenna to practical use is the RF nonlinearity of a variable capacitance diode. When the ESPAR antenna is used as a high-output transmitting antenna, harmonic distortion and intermodulation distortion may occur due to the RF nonlinearity of the variable capacitance diode. Here, using the film-type ESPAR antenna device 100a according to the fourth embodiment as the antenna device to be measured, a method for measuring the RF nonlinear distortion and the intermodulation distortion and the results thereof will be described below. It should be noted that the measurement of the transmission wave of the antenna is not a far-field measurement, but is characterized in that the measurement cost and time are greatly reduced by a very near-field measurement using a small anechoic chamber 90.

The variable capacitance diodes 14, 14a, 14b, 14c, and 4 in the fourth embodiment used in this experiment.
14d is a 1SV287 type variable capacitance diode manufactured by Toshiba Corporation. The capacitance at zero bias is 8pF, the capacitance at reverse bias voltage of 20V is 0.7pF, the reverse withstand voltage is 30V,
The series resistance is 1.9Ω. The reverse voltage is 30 V, and the forward bias voltage is changed from 0.5 V to the reverse bias voltage 2.
The junction capacitance of the variable capacitance diode is controlled by a DC voltage up to 0V. According to the specification of the variable capacitance diode, the reactance value at this time is from 6.9Ω to 91.5Ω.
It varies almost linearly up to.

In this experiment, the single varactor type (SV) and the anti-series varactor type (ASV) shown in FIGS.
The ESPAR antenna device 100a provided with the variable reactance circuit of P) is used as the antenna device to be measured. Hereinafter, the former is referred to as the SV ESPAR antenna device 100a, and the latter is referred to as the ASVP ESPAR antenna device 100a. ASV
P has the same junction capacitance of one variable capacitance diode as SV, but the RF current and RF voltage generated in one variable capacitance diode are both half of SV. Therefore, assuming that the RF current flowing through the variable capacitance diode is the same, the ASVP of the RF current flowing through the dipole of each parasitic element is twice the SV. In other words, ASVP is more
A 6 dB distortion resistance capability at F power is expected. In addition, the even-order distortion component on the dipole of each parasitic element ideally has the same amplitude on the upper and lower parts of the dipole and the opposite phase, so that an effect of canceling the second harmonic distortion can be expected.

FIG. 5 is a longitudinal sectional view showing a small anechoic box 90 accommodating the ESPAR antenna device 100a used in the embodiment of the experiment according to the present invention. As shown in FIG. 5, the small anechoic box 90 has a size of 630 mm × 630 mm × 630 mm, and a radio wave absorber 91 is mounted on its six inner surfaces. The radio wave absorber 91 is a pyramid having a sharp tip. It has a shape obtained by repeating the shape, and is made of polyurethane foam impregnated with carbon. The ESPAR antenna device 100a is supported by the support member 93 such that the ESPAR antenna device 100a is located at the center of the small anechoic box 90. Furthermore, CP-Nippon Vacuum Glass Co., Ltd.
Using a 2S type low disturbance multilayer substrate type magnetic field probe 92,
The detection tip is located at the center of the parasitic element (antenna element 13).
a, 13b are portions which are close to each other and where a variable reactance circuit is formed), and are arranged close to each other at a predetermined proximity distance d = 0.05 mm so as not to contact with the variable reactance circuit, and the extremely near field (magnetic field) of the antenna is measured. The measured output signal is shown in FIG.
Is input to the spectrum analyzer 107 shown in FIG. Therefore, the near-field (magnetic field) of the antenna exhibits a value substantially proportional to the high-frequency current flowing near the variable reactance circuit. By observing the frequency spectrum of the measurement output signal of the magnetic field, the fundamental wave and harmonics of the high-frequency current are measured. The power level of the wave component can be measured. In this embodiment, the experiment cost is significantly reduced by a very near-field (reactive field) measurement technique using a low disturbance probe magnetic field probe 92 and a small anechoic chamber 90.

FIG. 6 is a block diagram of a measuring circuit for measuring harmonic distortion according to a first embodiment of the present invention.

In the measuring circuit of FIG. 6, a high-frequency signal transmitted from the high-frequency signal generator 101 is converted into a high-frequency power amplifier (amplification degree 20 dB, 1 dB gain compression point + 28 dBm) 1
02, the two isolators 103,
105 and two band-pass filters 104 and 106, and input to the feeding point (RF terminal) of the excitation element A10 of the ESPAR antenna device 100a. Here, the purpose of inserting the isolators 103 and 105 is to remove spurious components such as standing waves and harmonics on the circuit. In order to suppress harmonics generated by the nonlinearity of the high-frequency power amplifier 102, two band-pass filters (center frequency: 2.45)
(0 GHz, bandwidth: 150 MHz) 104 and 106 were used. Further, the spectrum analyzer 107 observes the signal power levels of the fundamental wave, the second harmonic, and the third harmonic of the antenna from the very near field of the ESPAR antenna device 100a detected using the magnetic field probe 92 shown in FIG.
ESPAR antenna device 100a used in this embodiment
Since all the non-exciting elements are the same, any one of them is measured as a representative. Table 1 shows parameters for measuring harmonic distortion.

[0059]

[Table 1] Harmonic distortion measurement parameters ――――――――――――――――――――――――――――――――――― Item Symbol Unit Value ―――― ――――――――――――――――――――――――――――――――― SV, ASVP type variable reactance element configuration of the antenna to be measured ―――― ――――――――――――――――――――――――――――――― Frequency f GHz 2.484 ――――――――――――― ---------------------- antenna input power P _in dBm 20.7~28.1 --------------- ―――――――――――――――――――― Bias voltage V _cont V −0.5 (all elements) ――――――――――――――――― ――――――――――――――――――

SV and ASVP ESPAR antenna device 10
0a (f = 2.484 GHz), 2nd harmonic (2f = 4.968 GHz), and 3rd harmonic (3f = 2.484 GHz)
FIG. 7 shows the measurement results of the relative output power level with respect to the antenna input power Pin of 7.452 GHz). It is clear from FIG. 7 that the levels of the fundamental wave of the SV and the ASVP are almost the same, whereas the levels of the second harmonic and the third harmonic of the ASVP are smaller than the corresponding ones of the SV. Since the slopes of the second and third harmonics of SV and ASVP are almost twice and three times that of the fundamental wave, it is considered that the reliability of this measurement result is high.

Next, FIG. 8 shows the relative output power (dBc) of the second harmonic with respect to the fundamental waves of SV and ASVP when the antenna input power Pin is changed, and the relative output power of the third harmonic with respect to the fundamental wave. (DBc) is shown in FIG.
From these measurement results, it is possible to confirm the effect of suppressing the nonlinear distortion due to the connection of the anti-series varactor (particularly, the second harmonic distortion is improved by 20 dB or more). Antenna input power Pin is + 28d
ASVP secondary and 3 at Bm (640 mW)
The second harmonic distortion is suppressed to -80 dBc or less. FIG.
9 is about 10 dBc, which is as designed, whereas the second harmonic distortion shown in FIG. 9 is improved by 20 dB or more. This is presumably because the even modes of the second harmonic distortion on the six parasitic elements (dipoles) printed on the dielectric film 80 effectively cancel each other.

FIG. 10 is a block diagram of a measuring circuit for measuring intermodulation distortion according to a second embodiment of the present invention.

In FIG. 10, there are provided high frequency signal generators 101 and 111 which respectively generate two high frequency signals which are close to each other but differ by, for example, 1 kHz. A high-frequency signal generated by one high-frequency signal generator 101 is input to a Wilkinson power combiner 108 via a high-frequency power amplifier 102, an isolator 103, and a band-pass filter 104. Also, the other high-frequency signal generator 1
The high-frequency signal generated by the high-frequency power amplifier 1
12. Isolator 113 and bandpass filter 114
Is input to the Wilkinson-type power combiner 108. The high-frequency power amplifiers 102 and 112 have the same specifications as those of the high-frequency power amplifier 102 shown in FIG.
It has the same specifications as Further, similarly to the harmonic distortion measurement circuit shown in FIG.
103 and 113 and bandpass filters 104 and 1 to prevent harmonic spurious and standing waves due to
14 is inserted.

The power combiner 108 combines the power of the two input high-frequency signals, and then inputs the resultant signal to the excitation element A0 of the ESPAR antenna device 100a placed in the small anechoic box 90. At this time, the low disturbance multi-layer substrate magnetic field probe 92
After the measurement output signal detected in step (1) is amplified by the low noise amplifier 109, the signal is observed by the spectrum analyzer 107.
Table 2 shows measurement parameters according to the second example.

[0065]

[Table 2] Intermodulation distortion measurement parameters ――――――――――――――――――――――――――――――――――――― Item Symbol Unit Value ―――― ――――――――――――――――――――――――――――――――― SV, ASVP type variable reactance element configuration of the antenna to be measured ―――― ――――――――――――――――――――――――――――――― Frequency f GHz 2.484,2.484001 ――――――――――――― ---------------------- antenna input power P _in dBm 11.5~23.1 --------------- ―――――――――――――――――――― Bias voltage V _cont V 0-20 (all elements) ―――――――――――――――――― ―――――――――――――――――

ASVP and SV ESPAR antenna device 10
0a and the relative output power of the third-order intermodulation distortion wave (d
The measurement results of B) are shown in FIGS. 11 and 12, respectively. This is a result when the antenna input power Pin is 17.8 dBm and the bias voltage V _cont is 15 V. 11 and 12, the intersection of the plot line of the fundamental wave and the plot line of the third-order intermodulation distortion wave is called a third-order intercept point IP3. FIG.
1 and FIG. 12, it can be seen that the antenna input power Pin of the tertiary intercept point IP3 of ASVP is about 2 dB larger than that of SV.

Next, the bias voltage V _{cont is set} to 20 V
FIG. 13 shows the relative output power (dBc) of the third-order cross-distorted wave with respect to the fundamental wave when the antenna input power Pin to the ESPAR antenna device 100a is changed. Regarding the ASVP third-order intermodulation distortion, when the antenna input power Pin is +20 dBm (100 mW), the relative output power (dB) of the third-order cross distortion wave with respect to the fundamental wave
c) is about -55 dBc. Also, the relative output power (dBc) of the third-order cross distortion wave with respect to the ASVP fundamental wave
Is S when the antenna input power Pin is 11.5 dBm.
It can be seen that V is about 10 dB smaller than that of V.

Further, the antenna input power Pin is set to 21.
When fixed at 7 dBm, the ESPAR antenna device 100a
Output power (dB) of the third-order intermodulation distortion wave with respect to the fundamental wave when the bias voltage V _cont applied to
c) is shown in FIG. From FIG. 14, the bias voltage V
The maximum value of the difference between ASVP and SV by _cont is about 5 dB
It became. ASVP at all bias voltages V _cont
Was found to have better characteristics than SV.

FIGS. 15 and 16 show SV and ASV respectively including the measurement data of FIG.
In the case of P, when the antenna input power Pin is used as a parameter and the bias voltage V _cont is changed,
Relative output power of third-order intermodulation distortion wave with respect to fundamental wave (dB)
c) is shown. As is clear from FIGS. 15 and 16, when the input power Pin value of the ESPAR antenna apparatus 100a is increased, the relative output power (dBc) of the third-order intermodulation distortion wave with respect to the fundamental wave is relatively increased, and the same. , The relative output power (dBc) of the third-order intermodulation distortion wave with respect to the fundamental wave increases as the bias voltage V _cont decreases. That is, when the bias voltage V _cont applied to the variable capacitance diode is reduced, a quantitative relationship is obtained in which the third-order intermodulation distortion wave increases.

Finally, FIG. 17 shows the measurement results of the antenna input power Pin (dBm) at the tertiary intercept point IP3 when the bias voltage V _cont is changed.
In ASVP, third-order intercept point I when two waves are input
The antenna input power Pin of P3 is +43 to +48 dBm
(20-63 W) or more. The higher the bias voltage V _cont applied to the variable capacitance diode is, the larger the antenna input power Pin of the tertiary intercept point IP3 is, that is, the smaller the distortion is.

As described above, according to the present embodiment,
R of the variable capacitance diode of the ESPAR antenna device 100a
The harmonic distortion and intermodulation distortion caused by the F nonlinearity were experimentally clarified. Low disturbance multilayer substrate type magnetic field probe 9
2 and the small near-field anechoic chamber 90 for measuring the near-field (reactive field) greatly reduced experimental costs. As an antenna to be measured, a prototype film-type lightweight ESPAR antenna device 100a was used. This antenna device 1
00a is loaded with a new variable reactance circuit (FIG. 4B) using an anti-series variable capacitance diode pair.
As a result of the measurement, a non-linear distortion suppression effect (especially, the second harmonic distortion was improved by 20 dB or more) was obtained as compared with the case where the single variable capacitance diode of FIG. 4A was used. 2 when antenna input power Pin is +28 dBm (640 mW)
The second and third harmonic distortions were -80 dBc or less, and the antenna input power Pin at the third intercept point when two waves were input obtained a characteristic of +43 to +48 dBm (20 to 60 W) or more.

<Modifications> The array antenna device used in the above embodiment may be used for transmission,
It may be used for reception.

In the above embodiment, the high-frequency current flowing through the non-excitation element of the ESPAR antenna device is measured. However, the high-frequency current flowing through the excitation element may be measured by a similar method.

In the above embodiments, the method of measuring the ESPAR antenna device has been described. However, the present invention is not limited to this, and the same applies to an antenna device having at least one antenna element or an array antenna device. In this way, a high frequency current flowing through the antenna element can be measured by detecting a magnetic field from the antenna element.

In the above embodiment, the high-frequency current near the center of the antenna element (dipole) is measured. However, the present invention is not limited to this, and the magnetic field probe 92 is moved while moving the magnetic field probe 92 in the longitudinal direction of the antenna element. Is measured, the distribution (or magnetic field distribution) of the high-frequency current in the longitudinal direction of the antenna element can be measured.

In the above embodiment, the ESPAR antenna device 100a is housed in the small anechoic box 90. However, the present invention is not limited to this. For example, a non-reflective radio wave environment in which radio waves are not substantially reflected may be used.

In the above-described second embodiment, two high-frequency signals are input. However, the present invention is not limited to this.
Intermodulation distortion may be measured by inputting one or more high-frequency signals.

[0078]

As described above in detail, according to the array antenna apparatus of the present invention, in the conventional ESPAR antenna, each variable reactance circuit includes at least one pair of variable reactance elements connected in opposite directions. It is configured with. Therefore, non-linear distortion such as second harmonic distortion and third harmonic distortion and intermodulation distortion can be suppressed.

Further, in the above array antenna device,
Preferably, each of the variable reactance circuits is configured by connecting at least one pair of circuit groups in which each circuit group includes a plurality of variable reactance elements connected in parallel in opposite directions. At least one pair of circuit groups, each of which includes a plurality of variable reactance elements connected in series and in parallel, are connected in opposite directions. Therefore, non-linear distortion such as second harmonic distortion and third harmonic distortion and intermodulation distortion can be suppressed. Also, since the variable capacitance diodes are connected in parallel or in series and in parallel in each circuit group, it is possible to provide a high power array antenna device that can withstand a large current and / or a high voltage.

According to another aspect of the method of measuring an array antenna device according to the present invention, the array antenna device is housed in an anechoic chamber, a high-frequency signal is supplied to the excitation element, and the plurality of balanced non-excitation A magnetic field detecting means is provided in proximity to one of the elements so as not to come into contact with the element, and a high-frequency current of the balanced non-excited element is detected by detecting a magnetic field of the balanced non-excited element. Therefore, the high-frequency current of the balanced non-exciting element of the array antenna device can be accurately detected, and the distribution can be measured by measuring the high-frequency current along the element.

According to a method of measuring an array antenna device according to another invention, the array antenna device is housed in an anechoic chamber, a high-frequency signal of a fundamental wave is supplied to the excitation element, and the plurality of balanced non-balanced antennas are supplied. A magnetic field detecting means is provided so as not to come into contact with one of the excitation elements, a high-frequency current is detected by detecting a magnetic field of the balanced non-excitation element, and based on the detected high-frequency current, A signal level of at least one of a fundamental wave and a harmonic is detected.
Therefore, it is possible to accurately detect the signal levels of the fundamental wave and the harmonic in the high-frequency current of the balanced passive element of the array antenna device. This makes it possible to measure nonlinear distortion such as second harmonic distortion and third harmonic distortion.

According to a method for measuring an array antenna device according to still another invention, the array antenna device is housed in an anechoic box, and high-frequency signals of at least two fundamental waves close to each other are supplied to the excitation element. A magnetic field detecting means is provided so as not to contact one of the plurality of balanced non-exciting elements, and a high-frequency current is detected by detecting a magnetic field of the balanced non-exciting element. A signal level of at least one of a fundamental wave and a harmonic is detected based on the high frequency current. Therefore, when a signal of two frequencies is input to the array antenna device, it is possible to accurately detect the signal levels of the fundamental wave and the harmonics in the high-frequency current of the balanced non-exciting element of the array antenna device. Thereby, the intermodulation distortion can be measured.

According to still another aspect of the present invention, there is provided a method of measuring an antenna device having at least one antenna element, wherein the antenna device is housed in an anechoic box, A high-frequency signal is supplied to the antenna element, a magnetic field detecting means is provided close to the antenna element so as not to contact the antenna element, and a high-frequency current of the antenna element is detected by detecting a magnetic field of the antenna element. Therefore, the high-frequency current of the antenna element of the antenna device can be accurately detected, and the distribution can be measured by measuring the high-frequency current along the element.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of a dipole-type parasitic element A11 used in an array antenna device according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a configuration of a dipole-type parasitic element A12 used in an array antenna device according to a second embodiment of the present invention.

FIG. 3 is a circuit diagram illustrating a configuration of a dipole-type parasitic element A13 used in an array antenna device according to a third embodiment of the present invention.

FIG. 4 is a perspective view illustrating a configuration of an array antenna device according to a fourth embodiment of the present invention and used in an experimental example, and a circuit diagram illustrating a configuration of a variable reactance element circuit used therein. FIG. 2A is a circuit diagram showing a single-varactor (SV) variable reactance element circuit according to a conventional example, and FIG. 2B is a circuit diagram showing an anti-series varactor (ASVP) variable reactance element circuit according to the embodiment. FIG.

FIG. 5 is a longitudinal sectional view showing a small anechoic box 90 accommodating the ESPAR antenna device 100a used in an example of an experiment according to the present invention.

FIG. 6 is a block diagram of a measurement circuit that measures harmonic distortion according to the first embodiment of the present invention.

7 is a graph showing the measurement results of the measurement circuit of FIG. 6 and showing the relative output power of the fundamental wave, the second harmonic, and the third harmonic when the antenna input power is changed.

8 is a graph showing a result of measurement by the measurement circuit of FIG. 6, showing a relative output power of a second harmonic with respect to a fundamental wave when an antenna input power is changed.

9 is a graph showing the measurement results of the measurement circuit of FIG. 6 and showing the relative output power of the third harmonic with respect to the fundamental wave when the antenna input power is changed.

FIG. 10 is a block diagram of a measurement circuit for measuring intermodulation distortion according to a second embodiment of the present invention.

11 is a measurement result obtained by the measurement circuit of FIG. 10 and shows a fundamental wave and a third-order mutual wave when an antenna input power is changed in an ESPAR antenna device 100a using a variable reactance element circuit of ASVP (Example). It is a graph which shows the relative output power of a modulation distortion wave.

12 shows measurement results obtained by the measurement circuit shown in FIG. 10, and shows a fundamental wave and a third-order mutual wave when an antenna input power is changed in an ESPAR antenna device 100a using an SV (conventional example) variable reactance element circuit. It is a graph which shows the relative output power of a modulation distortion wave.

13 is a graph showing the measurement results of the measurement circuit of FIG. 10 and showing the relative output power of the third-order intermodulation distortion wave with respect to the fundamental wave when the antenna input power is changed.

14 shows measurement results obtained by the measurement circuit shown in FIG. 10, and shows an ESPAR antenna device 100 using variable reactance element circuits of SV (conventional example) and ASVP (example).
7A is a graph showing the relative output power of the third-order intermodulation distortion wave with respect to the fundamental wave when the bias voltage is changed in FIG.

FIG. 15 is a measurement result obtained by the measurement circuit of FIG. 10 and shows a third-order intermodulation with respect to a fundamental wave when a bias voltage is changed in an ESPAR antenna device 100a using an SV (conventional example) variable reactance element circuit. It is a graph which shows the relative output power of a distortion wave.

FIG. 16 shows a measurement result obtained by the measurement circuit shown in FIG. 10, and shows a third-order intermodulation with respect to the fundamental wave when the bias voltage is changed in the ESPAR antenna device 100a using the variable reactance element circuit of ASVP (Example). It is a graph which shows the relative output power of a distortion wave.

FIG. 17 shows measurement results obtained by the measurement circuit shown in FIG. 10, and shows an ESPAR antenna device 100 using variable reactance element circuits of SV (conventional example) and ASVP (example).
10A is a graph showing the antenna input power at the third intercept point when the bias voltage is changed in FIG.

FIG. 18 is a block diagram showing a configuration of a conventional array antenna control device.

FIG. 19 is a plan view showing a configuration of a dipole-type parasitic element A10 used in the related art.

20 is a diagram showing a variable capacitance diode 14 which is an example of the variable reactance element 12 of FIG. 19 used in the prior art.

[Explanation of symbols]

A0, A10: Exciting elements, A1 to A6: Non-exciting elements, A11, A12, A13: Dipole type non-exciting elements. 11: ground conductor, 12: variable reactance element, 13a, 13b: antenna element, 14, 14a, 14b, 14c, 14d: variable capacitance diode, 15a, 15b, 15c: resistor, 17a, 17b, 17c: resistor, 20 ... Adaptive control type controller 21 Learning sequence signal generator 22 High frequency receiver 23 Demodulator 31-34 41-44 Variable capacitance diode 51-54 Connection point 61-62-71-72 ... Circuit group, 80 ... Dielectric film, 90 ... Small anechoic box, 91 ... Electromagnetic absorber, 92 ... Magnetic field probe, 100a ... Espa antenna device, 101,111 ... High frequency signal generator, 102,112 ... High frequency power amplifier, 103, 105, 113 ... isolator, 104, 106, 114 ... band-pass filter, 10 7: spectrum analyzer, 108: power combiner, 109: low noise amplifier.

 ──────────────────────────────────────────────────の Continuation of the front page (72) Inventor Han Blue 2-2-2 Kodai, Seika-cho, Soraku-gun, Kyoto Pref. Within the ATR Environmental Adaptive Communication Research Laboratory (72) Inventor Keizo Inagaki Kyoto Soraku 2-2-2 Kodai, Seika-cho, ATR F-term (reference) in ATR Environmental Adaptive Communications Laboratory 5J020 AA03 BA02 BC02 BC08 DA03 5J021 AA01 AB02 BA01 DB04 FA03 GA02

Claims (9)

[Claims] An excitation element for transmitting and receiving a radio signal; a plurality of balanced non-excitation elements provided at a predetermined distance from the excitation element; and a plurality of balanced non-excitation elements connected to the plurality of balanced non-excitation elements, respectively. A plurality of variable reactance circuits, and by changing the reactance value of each of the variable reactance circuits, the plurality of balanced non-exciting elements are operated as a director or a reflector, respectively, to improve the directional characteristics of the array antenna. In the array antenna device to be changed, each of the variable reactance circuits includes at least one pair of variable reactance elements connected in opposite directions. 2. The variable reactance circuit according to claim 1, wherein each of the circuit groups is configured by connecting at least one pair of circuit groups in a direction opposite to each other, the circuit groups each including a plurality of variable reactance elements connected in parallel. 2. The array antenna device according to claim 1, wherein: 3. Each of the variable reactance circuits is configured by connecting at least one pair of circuit groups, each of which includes a plurality of variable reactance elements connected in series and in parallel, in opposite directions. The array antenna device according to claim 1, wherein: 4. The variable reactance element according to claim 1, wherein each of said variable reactance elements comprises a variable capacitance diode having substantially the same applied voltage to junction capacitance characteristic. An array antenna device as described in the above. 5. The device according to claim 1, wherein a dielectric film is provided around the excitation element, and the plurality of balanced non-excitation elements are formed on the dielectric film. The array antenna device according to any one of the above. 6. The method for measuring an array antenna device according to claim 1, wherein the array antenna device is housed in a non-reflective radio wave environment, and a high-frequency wave is applied to the excitation element. Supplying a signal; and providing a magnetic field detecting means in close proximity to one of the plurality of balanced non-exciting elements so as not to contact the one; Detecting a high-frequency current of the parasitic element. 7. The method for measuring an array antenna device according to claim 1, wherein the array antenna device is housed in a non-reflective radio wave environment, and Feeding a high-frequency signal of a wave, and providing a magnetic field detecting means in close proximity so as not to contact one of the plurality of balanced passive elements, and detecting a magnetic field of the balanced passive element. A method for measuring an array antenna device, comprising: detecting a high-frequency current; and detecting a signal level of at least one of a fundamental wave and a harmonic based on the detected high-frequency current. 8. The method for measuring an array antenna device according to claim 1, wherein the step of housing the array antenna device in a non-reflective radio wave environment includes the steps of: Supplying high frequency signals of at least two fundamental waves which are close to each other; and providing magnetic field detecting means so as not to be in contact with one of the plurality of balanced non-exciting elements; Detecting a high-frequency current by detecting a magnetic field of, and detecting a signal level of at least one of a fundamental wave and a harmonic based on the detected high-frequency current. Measurement method of array antenna device. 9. A method for measuring an antenna device provided with at least one antenna element, comprising: housing the antenna device in a non-reflective radio wave environment; feeding a high-frequency signal to the antenna device; Providing a magnetic field detecting means close to the element so as not to contact the element, and detecting a high frequency current of the antenna element by detecting a magnetic field of the antenna element.