JP2008211668A - Adaptive directional reception apparatus, automobile and mobile information equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adaptive directional reception apparatus which is easily small-sized and reduces limitations in mounting, an automobile with the adaptive directional reception apparatus mounted thereon, and mobile information equipment. <P>SOLUTION: The adaptive directional reception apparatus comprises: antenna elements A1-A3 each outputting an excited current by a radio signal; reflection current output circuits 31-33 each inputting the excited current and outputting a reflection current of the excited current; a synthesizer circuit 2 which vector-synthesizes the reflection currents to produce a synthetic signal; a baseband signal generation circuit 1 which generates a demodulation signal from the synthetic signal; a target function calculator 41 for generating a target function from the demodulation signal; and an adjuster 42 which adjusts phases of the reflection currents by controlling loads of the reflection current output circuits 31-33 so as to bring the target function to an optimal value. The adaptive direction reception apparatus demodulates the radio signals while controlling directivity of adaptive antennas constituting an opening by means of the antenna elements A1-A3 by adjusting the reflection currents. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an antenna for wireless communication, and more particularly, to an adaptive directional receiver using an adaptive antenna capable of obtaining a high signal-to-interference cancellation ratio (SIR) in mobile communication, an automobile mounted with the adaptive directional receiver, and It relates to portable information equipment.

  When receiving FM broadcasts etc. while traveling for a long time in the United States, Australia, China, etc. by automobile, or in environments that are susceptible to fading such as urban areas where high-rise buildings are densely packed When receiving, or when receiving a radio signal with a mobile phone, it is difficult to receive stably, and directivity control using array antenna technology is required.

  A phased array antenna is a functional antenna comprising a plurality of antennas (radiating elements) whose electronic directivity can be controlled. The use of multiple radiating elements, phase shifters and control circuits has limited their use to special applications such as military radar. However, in recent years, the cost of microwave hardware has been reduced, and it has come to be used for satellite-mounted repeaters and public radio base stations as communication applications. In order to maintain high transmission quality with low power in wireless mobile communication, an antenna control technique that maximizes the gain of a desired wave or minimizes the influence of an interference wave on the desired wave is useful. A functional antenna that is automatically controlled by an optimization algorithm whose directivity is adapted to the radio wave environment is called an “adaptive antenna”. Specifically, the radio wave environment changes every moment, such as directing the main beam in the direction of arrival of the desired wave, directing the null point in the direction of arrival of the interference wave, maximizing the signal-to-interference noise ratio SINR, and combining and compensating for multipath waves It is an antenna control technology that autonomously adapts the antenna directivity. An adaptive antenna uses signals received by a plurality of antennas and attempts to maximize a signal-to-interference cancellation ratio (SIR) by a spatial filter.

In recent years, an electronic scanning waveguide (ESPAR) antenna has been energetically studied as an adaptive antenna with a simple hardware configuration (see Patent Documents 1 to 3). The aperture of the electronic scanning waveguide antenna is composed of one radiating element and a plurality of parasitic elements arranged around the radiating element. The radiating element and the parasitic element are electromagnetically coupled, and a part of the reception signal of the parasitic element is received by the radiating element by the maximum radiation of the signal received by the parasitic element. A variable reactance element such as a varactor is connected to the output of the parasitic element, and by appropriately changing the reactance value, the induced current generated in the parasitic element is controlled to change the radiation directivity. In the electronic scanning waveguide antenna, the directivity that maximizes the signal-to-interference-to-noise ratio SINR is formed by finding the reactance value that maximizes the correlation coefficient between the reference signal sequence and the radiating element reception signal by a gradient method or the like. .
JP 2003-142926 A JP 2003-209426 A JP 2003-258532 A

  A conventional adaptive antenna requires a plurality of transmission / reception systems, has a large apparatus size and power consumption, and cannot be used in addition to existing equipment. Therefore, the cost cannot be reduced and it is difficult to apply to consumer wireless terminal products. There is a method of using an excitation element and a non-excitation element electromagnetically coupled to the excitation element as an adaptive antenna having a transmission / reception system of one channel that can be used in addition to a conventional device. I can't use it. Further, since the antenna elements are used close to each other, there is a problem that restrictions on mounting occur.

  In view of the above problems, an object of the present invention is to provide an adaptive directional receiver that is easy to downsize and has few restrictions on mounting, and an automobile and a portable information device on which the adaptive directional receiver is mounted.

  In order to achieve the above object, according to the first aspect of the present invention, (a) a plurality of antenna elements constituting the antenna array, and (b) a load for adjusting the ground reactance of each of the plurality of antenna elements, respectively. A plurality of reflected current output circuits that output the reflected current from the load, and (c) a combined circuit that generates a combined signal by vector combining the reflected currents output by the plurality of reflected current output circuits. And (d) a baseband signal generation circuit that generates a demodulated signal from the synthesized signal, and (e) an operation for obtaining an objective function from the demodulated signal and controlling the load value so that the objective function becomes an optimum value. And an adaptive directivity receiver that controls the directivity of the antenna array by controlling the value of the load.

According to a second aspect of the present invention, (a) a plurality of antenna elements that are arranged in at least one of a bonnet, a front end or a rear end of a roof, an A pillar, or a rear window or a rear side window and constitute an antenna array; (B) a plurality of reflected current output circuits each having a load for adjusting the ground reactance of each of the plurality of antenna elements and outputting a reflected current from the load; and (c) a plurality of reflected current output circuits. Vector synthesis of the reflected currents to be output, respectively, a synthesis circuit for generating a synthesized signal, (d) a baseband signal generating circuit for generating a demodulated signal from the synthesized signal, and (e) generating an objective function from the demodulated signal, An arithmetic processing circuit is provided for controlling the load value so that the objective function becomes an optimum value. Characterized in that by controlling the directivity of the array is an automobile equipped with a receiver for performing wireless communication.
A third aspect of the present invention includes: (a) a plurality of antenna elements that constitute an antenna array by selecting a plurality from at least one of a rod-shaped antenna, an inverted-F antenna, and a substrate antenna; A plurality of reflected current output circuits each having a load for adjusting each ground reactance of the antenna element and outputting a reflected current from the load; and (c) a reflected current output by each of the plurality of reflected current output circuits. (D) a baseband signal generation circuit that generates a demodulated signal from the synthesized signal, and (e) an objective function is generated from the demodulated signal, and this objective function is optimal. And an arithmetic processing circuit for controlling the load values so that the antenna array has a value, and by controlling the directivity of the antenna array by controlling the load value Characterized in that it is a portable information apparatus for performing communications.

  According to the present invention, it is possible to provide an adaptive directional receiver that is easy to downsize and has few restrictions on mounting, and an automobile and a portable information device on which the adaptive directional receiver is mounted.

  Next, first to third embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the following first to third embodiments exemplify apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention includes an antenna element, The configuration and arrangement of circuit elements and circuit blocks are not specified as follows. The technical idea of the present invention can be variously modified within the technical scope described in the claims.

(First embodiment)
As shown in FIG. 1, the adaptive directivity receiving apparatus according to the first embodiment of the present invention includes a plurality of antenna elements A1 to Am (m is a positive integer of 2 or more) for receiving a radio signal, and a plurality of antenna elements A1 to Am. It is each of the antenna elements A1 to Am connection has a load of adjusting the respective grounding reactances of the plurality of antenna elements A1 to Am, and the reflection current output for outputting the reflected current Ir ₁ ~Ir _m from the load, respectively a circuit 31-3m, the reflection current Ir ₁ ~Ir _m reflection current output circuit 31-3m outputs each vector synthesis, the combining circuit 2 for generating a composite signal CS, generates a demodulated signal from the composite signal CS A baseband signal generation circuit 1.

  Here, the “antenna element” functions as an excitation element (feeding element) that outputs a radio signal captured from the air to the receiving device side. An aperture of the adaptive antenna is configured by the arrangement of the plurality of antenna elements A1 to Am. In the present specification including the second embodiment, as shown in FIG. 1, when m = 3, that is, the first to third reflected currents in the first to third antenna elements A1 to Am, respectively. The technical contents will be described by taking the case where the output circuits 31 to 33 are connected as an example. However, it is a matter of course that the present invention is not limited only to the case of m = 3 (however, the practical point of view, particularly the miniaturization, From the viewpoint of cost reduction and speedup, m = 3 or m ≧ 3 and a value close to 3 is preferable.)

In other words, when m = 3, the first reflected current output circuit 31 includes the first directional coupler DC ₁ connected to the first antenna element A1 and the first directional coupler DC _1. And a first variable reactance circuit Zn ₁ as a load for adjusting the ground reactance of the first antenna element A 1. The first variable reactance circuit Zn ₁ receives the excitation current Id ₁ from the first antenna element A 1 via the first directional coupler DC ₁ and reflects the reflected current Ir ₁ . The first directional coupler DC ₁ is adapted to transmit the excitation current Id ₁ in which the first antenna element A1 is output to the first variable reactance circuit Zn _1, the first variable reactance circuit Zn ₁ is reflected reflection The current Ir ₁ is output to the synthesis circuit 2.

The second reflection current output circuit 32, the second directional coupler DC ₂ of which is connected to the second antenna element A2, the second is connected to the directional coupler DC _2, the second A second variable reactance circuit Zn ₂ is provided as a load for adjusting the ground reactance of the antenna element A2. The second variable reactance circuit Zn ₂ receives the excitation current Id ₂ from the second antenna element A 2 via the second directional coupler DC ₂ and reflects the reflected current Ir ₂ . The second directional coupler DC ₂ transmits the excitation current Id ₂ output from the second antenna element A ₂ to the second variable reactance circuit Zn ₂ and the reflection reflected by the _second variable reactance circuit Zn _2. The current Ir ₂ is output to the synthesis circuit 2. Further, the third reflection current output circuit 33 includes a third directional coupler DC ₃ which is connected to the third antenna element A3, are connected to the third directional coupler DC _3, third A third variable reactance circuit Zn ₃ is provided as a load for adjusting the ground reactance of the antenna element A3. The third variable reactance circuit Zn ₃ receives the excitation current Id ₃ from the third antenna element A3 via the third directional coupler DC ₃ and reflects the reflected current Ir ₃ . The third directional coupler DC ₃ transmits the excitation current Id ₃ output from the third antenna element A ₃ to the third variable reactance circuit Zn ₃ and the reflection reflected by the _third variable reactance circuit Zn _3. The current Ir ₃ is output to the synthesis circuit 2.

The adaptive directional receiving apparatus shown in FIG. 1, as the objective function obtained from the demodulated signal becomes optimum, and controls each of the load of the antenna element A1~A3 the (ground reactance) respectively, reflecting current Ir ₁ ~ By adjusting the phase of Ir ₃ , the radio signal is demodulated while controlling the directivity of the adaptive antenna that forms the aperture by the antenna elements A1 to A3.

A baseband signal generation circuit 1 is connected to the synthesis circuit 2, and a synthesized signal CS generated by vector synthesis of radio signals captured by the antenna elements A1 to A3 from the air is a low noise amplifier 11 of the baseband signal generation circuit 1. Is input. A digital signal processor (DSP) 4 as an “arithmetic processing circuit” is connected to the output side of the baseband signal generation circuit 1 to process the demodulated signal generated by the baseband signal generation circuit 1. The arithmetic processing circuit (DSP) 4 obtains an objective function from the demodulated signal, and first, second, and third variable reactances Zn ₁ , Zn ₂ , Zn ₃ as loads so that the objective function becomes an optimum value. The reactance value of each is controlled.

FIG. 2 shows a configuration example of the _first variable reactance circuit Zn ₁ that is a load for adjusting the ground reactance of the first antenna element A1. The first variable reactance circuit Zn ₁ includes a first inductor L ₁ having _one end connected to the directional coupler DC ₁ , a second inductor L ₂ connected to the other end of the first inductor L ₁ , and a second inductor. a capacitor C ₁ connected to L _2, with a variable capacitance diode D ₁ connected to the capacitor C _1, an anode side of the variable capacitance diode D ₁ is grounded. One end of the third inductor L ₃ is connected to the connection point of the second inductor L ₂ and the capacitor C ₁ , and the other end of the third inductor L ₃ is grounded. That is, the third inductor L ₃ is connected in parallel to a series connection circuit composed of the capacitor C ₁ and the variable capacitance diode D ₁ . In addition, the other terminal of the resistor R having one terminal connected to the connection point between the capacitor C ₁ and the variable capacitance diode D ₁ is connected to the DA converter 51. For example, the inductances of the first inductor L ₁ , the second inductor L ₂ , and the third inductor L ₃ are 0.1 μH, 0.22 nH, and 0.22 nH, respectively, and the capacitance of the capacitor C ₁ is 0.1 μF, resistance The resistance value of R can be about 100 kΩ.

The configurations of the second and third variable reactances Zn ₂ and Zn ₃ that are loads for adjusting the ground reactance of the second and third antenna elements A2 and A3 are the same as those of the first variable reactance circuit Zn ₁ .

The first, second, and third variable reactances Zn ₁ , Zn ₂ , and Zn ₃ are connected to a DSP 4 as an arithmetic processing circuit via DA converters 51, 52, and 53, respectively.

  The baseband signal generation circuit 1 includes a low noise amplifier 11 connected to the synthesis circuit 2, a mixer 12 connected to the low noise amplifier 11, and a local oscillator 18 connected to the mixer 12. The mixer 12 mixes the RF signal output from the low noise amplifier 11 and the RF signal output from the local oscillator 18 to generate a signal having an intermediate frequency (IF) of, for example, 10.7 MHz.

  In the baseband signal generation circuit 1, the RF signal output from the local oscillator 18 and the RF signal output from the synthesis circuit 2 are transmitted to the IF filter 13 mixed by the mixer 12. An automatic gain adjustment (AGC) amplifier 14 is connected to the IF filter 13, and a demodulator 15 is connected to the AGC amplifier 14. The IF filter 13 extracts the difference frequency between the RF signal output from the synthesis circuit 2 and the RF signal output from the local oscillator 18, and the AGC amplifier 14 amplifies the IF signal that is the difference frequency. A baseband signal is generated from the IF signal by the demodulator 15. The baseband signal is further converted into a digital signal by the A / D converter 17 and input to the arithmetic processing circuit (DSP) 4.

  FIG. 3 is a logical block diagram for mainly explaining the contents of the DSP 4 as the arithmetic processing circuit shown in FIG. That is, FIG. 3 shows that the arithmetic processing circuit (DSP) 4 includes an objective function calculation device 41, an adjustment device 42, and a variable reactor driver 43 as its logical configuration.

As shown in FIG. 1, the A / D converter 17 generates a demodulated signal S _R as a digital baseband signal. The demodulated signal S _R is input to the arithmetic processing circuit (DSP) 4, and the arithmetic processing circuit (DSP) 4 performs demodulation using an objective function calculation device 41 and an adjustment device 42 as shown in FIG. The signal S _R is signal-processed, and control signals Sc ₁ , Sc ₂ , Sc ₃ are generated. The control signals Sc ₁ , Sc ₂ , Sc ₃ are output to the variable reactor driver 43. The variable reactor driver 43 outputs reactance control voltages V ₁ , V ₂ , and V ₃ to the variable reactance circuits Zn ₁ , Zn ₂ , and Zn ₃ , and the variable reactance circuits that configure the reflected current output circuits 31 to 33, respectively. The ground reactance values of Zn ₁ , Zn ₂ , and Zn ₃ are controlled, and an adaptive beam is formed.

  In the adaptive antenna according to the first embodiment shown in FIGS. 1 to 3, extraction of radio signals captured from the air is performed from the antenna elements A1 to A3, and the entire directivity pattern is controlled to form an adaptive beam. To do. “Adaptive beam formation” refers to directivity control in which the main beam is directed to the desired wave arrival direction, the null point is directed to the interference wave arrival direction, and the signal-to-interference noise ratio SINR is maximized.

As shown in FIG. 3, the variable reactor driver 43 is connected to each of the variable reactance circuits Zn ₁ , Zn ₂ , Zn ₃ of the reflected current output circuits 31 to 33, and the variable reactance circuits Zn ₁ , Zn ₂ , The ground reactance value of Zn ₃ is controlled. The variable reactor driver 43 is a variable voltage DC power source that applies a reverse bias voltage to the variable capacitance diode D _{1 included in} each of the variable reactance circuits Zn ₁ , Zn ₂ , and Zn ₃ to change the capacitance. The variable reactors driver 43, the variable reactance circuit Zn _1, Zn _2, the reactance control voltage V ₁ applied to the Zn _3, V _2, V ₃ to be varied, respectively, the variable reactance circuit Zn _1, Zn _2, Zn ₃ the capacitance value of the variable capacitance diode D ₁ of the respective varactor circuits independently varied to control the ground reactance value, independently so that each becomes a desired value.

Thereby, the phase of the excitation current on the antenna elements A1 to A3 can be changed, and the directivity characteristics of the adaptive antenna can be changed. In the circuit illustrated in FIG. 2, since the insertion of the first inductor L ₁ fixed in series to each of the variable reactance circuit Zn _1, Zn _2, Zn _3, the variable reactance circuit Zn _1, Zn _2, Zn ₃ The ground reactance value can take a value ranging from a positive value to a negative value. If the variable reactance circuits Zn ₁ , Zn ₂ , and Zn ₃ are capacitive circuit elements, the ground reactance value is always a negative value. In any case, the variable reactance circuits Zn ₁ , Zn ₂ , Zn ₃ are derived from the first inductor L ₁ , second inductor L ₂ , third inductor L ₃ , capacitor C ₁ , resistor R, and variable capacitance diode D _{1 described above.} It is not limited to such a circuit, and any element that can control the ground reactance value may be used.

  In addition, as a physical configuration, a mode in which the baseband signal generation circuit 1, the objective function calculation device 41, and the adjustment device 42 shown in FIG. 3 are all mounted inside a car radio (FM receiver) is possible. Furthermore, the whole receiving apparatus shown in FIG. 1 can be mounted in a portable information processing device such as a mobile phone or a computer.

The output of the regulator 42 is connected to the variable reactors driver 43, the output of the variable reactors driver 43 is connected to the variable reactance circuit _{Zn 1, Zn 2, Zn 3} . The variable reactor driver 43 may also be incorporated in a car radio (FM receiver), a mobile phone, a portable information processing device, etc. together with the baseband signal generation circuit 1, the objective function calculation device 41, and the adjustment device 42.

The baseband signal generation circuit 1 demodulates the demodulated signal S _R from the composite signal CS outputted from the combining circuit 2. For example, in the case of a modulation method in which the desired wave has a constant envelope, such as analog FM, it is possible to form a blind beam by paying attention to constant amplitude. For example, the constant envelope signal algorithm (Constant Modulus Algorithm: CMA) evaluation function Q (X), which is an algorithm based on a constant envelope criterion using only prior knowledge that the envelope of a desired signal is constant, is Let p and q be positive integers:

Q (Zn) = E [|| y (t) | p -σ p | q] ····· (1)

It is. Zn = [Zn ₁ Zn ₂ Zn ₃ ] is a load connected to each of the antenna elements A1 to A3, y (t) is an antenna output, and P waves s _m (t) (m = 1) in the N element array 2,... P) is incident from direction ψ _m :

It is expressed. α _n (ψ _m ) is a response of a wave incident from the direction ψ _m of the n-th element. Also, i _n when the open-circuit voltage of 1V at the antenna occurs, a current to be output from the antenna element is represented as follows:

Za is the self-impedance of the antenna, and Xi is the reactor value (i = 1 to n). p and q are positive integers. In the first embodiment of the present invention, p = q = 2. Considering fading, σ uses a short interval average value. X that minimizes the evaluation function Q is obtained by a direct search method.

The demodulated signal S _R output from the baseband signal generation circuit 1 is input to the objective function calculation device 41 shown in FIG. The objective function calculation device 41, for example, detects the synchronization from the demodulated signal S _R and generates the reference signal S _S to obtain a correlation, and the correlation coefficient between the reference signal S _S and the demodulated signal S _R is an objective function (evaluation function). A correlator that outputs Q can be used. In addition to the correlator, the objective function calculation device 41 may output the difference power between the reference signal S _S and the demodulated signal S _R as an objective function (evaluation function) Q. As the objective function (evaluation function) Q, a signal-to-interference / noise ratio SINR can be adopted. However, in the following explanation, the objective function (evaluation function) Q is the phase of the reference signal S _S and the demodulated signal S _R. It is described as a relation number. The objective function (evaluation function) Q output from the objective function calculation device 41 is input to the adjustment device 42.

The adjustment device 42 searches by a direct search method, a gradient method, a sequential search method, or a genetic algorithm so that the input objective function (evaluation function) Q becomes an optimum value (maximum or minimum). The “direct search method” is a method for solving an optimization problem,
(A) Does not require the gradient of the objective function,
(B) Mathematical convergence is guaranteed,
(C) that moderate convergence is obtained;
In the following, the case where the direct search method is used will be described. However, the processing algorithm of the adjustment device 42 need not be limited to the direct search method.

  In the direct search method, a set of points (referred to as “mesh”) around the current point is searched, and in the minimization problem, a value whose objective function is lower than the current point is searched. If there is a low point, the current point is moved to a low point, the search is continued by enlarging the mesh, and if there is no low value, the procedure of reducing and re-searching the mesh is repeated to minimize the objective function (evaluation function) Q. . If the inverse of the objective function (evaluation function) Q or the negative value of Q is used, the maximum value can be searched.

For this reason, the adjusting device 42 includes initial setting means 421 for calculating the initial values of the variable reactance circuits Zn ₁ , Zn ₂ , Zn ₃ and the objective function value O ₀ at the initial setting, variable reactance circuits Zn ₁ , Zn ₂ , Zn Mesh creation means 422 for creating a mesh corresponding to _3; polling means 423 for calculating and evaluating (polling) an objective function value at each mesh point; optimum value / polling result for comparing current optimum value with polling result The comparison unit 424 compares the current optimum value with the polling result, and if there is a low point (or a high point), the current optimum value is updated to a low point (or a high point), the mesh size is increased, and a low value is obtained. If there is no (or a high value), the mesh size changing means 425 for reducing the mesh size and the convergence determining means 426 for determining the convergence are logically configured. Obtain. These initial setting means 421, mesh creation means 422, polling means 423, optimum value / polling result comparison means 424, mesh size changing means 425, and convergence determination means 426 may be configured by dedicated hardware (logic circuit). Alternatively, a general-purpose processor may be used and an equivalent function may be realized by software that controls the processor.

The adjustment device 42 having such a logical configuration searches for the control signals Sc ₁ , Sc ₂ , Sc for optimizing the values of the variable reactance circuits Zn ₁ , Zn ₂ , Zn _{3 based} on the result of searching by the direct search method. Generate as ₃ . The individual control signals Sc ₁ , Sc ₂ , Sc ₃ generated by the adjusting device 42 are output to the variable reactor driver 43. Variable reactors driver 43, in order to optimize the reactance of the variable reactance circuit Zn _1, Zn _2, Zn _3, the variable reactance circuit Zn _1, Zn _2, Zn ₃ reactance control voltages V ₁ to, V _2, V ₃ Is output.

<Antenna control method>
Using the flowchart shown in FIG. 4, the adaptive antenna control method shown in FIGS. 1 to 3, that is, the values of the variable reactance circuits Zn ₁ , Zn ₂ , and Zn ₃ by the adjusting device 42 are optimized, thereby the main beam. The directivity control (in the case where the optimum value is the maximum value) that maximizes the signal-to-interference / noise ratio SINR by directing to the desired wave arrival direction, the null point to the interference wave arrival direction, will be described. When the objective function is a correlation value, the inverse of the correlation value is minimized as the objective function. When the objective function (evaluation function) Q is the signal-to-interference / noise ratio SINR, the adjustment device 42 searches by the direct search method so that the input objective function (evaluation function) Q becomes maximum. When the objective function (evaluation function) Q is the difference power between the normative signal S _S and the demodulated signal S _R , the adjustment device 42 performs a direct search so that the input objective function (evaluation function) Q is minimized. Search by law.

(A) First, in step S101, the initial setting means 421 of the adjustment device 42 sets the antenna elements A1 to A3 with j = 1, K _j = 1, Z _j = [Z ₁ , Z ₂ , Z ₃ ] = 0. Are set to the initial values of the variable reactance circuits Zn ₁ , Zn ₂ , and Zn ₃ . Further, the objective function value O ₀ at this initial setting is calculated.
(B) Next, in step S102, the mesh creation means 422 of the adjustment device 42 creates mesh points corresponding to the antenna elements A1 to A3. For example, when the antenna elements A1 to A3 are monopole antennas arranged on a straight line, six mesh points are created.

(C) In step S103, the polling means 423 of the adjustment device 42 calculates and evaluates (polls) the objective function values O _{1 to} O ₆ at each mesh point.

(D) In step S104, after incrementing j = j + 1, in step S105, the optimum value / polling result comparing means 424 of the adjusting device 42 compares the current optimum value with the polling result. That is, it is determined whether or not there is a value smaller than the objective function value O ₀ in the initial setting among the objective function values O _{1 to} O ₆ at each mesh point.

(E) If there is a value smaller than the objective function value O ₀ in the initial setting among the objective function values O _{1 to} O ₆ at each mesh point, the process proceeds to step S106. In step S106, the mesh size changing means 425 of the adjustment device 42 updates the current optimum value O _j to a low point Z _j , sets K _j to 1.4 * K _j−1 , and sets the mesh size to a multiple of 1.4. Zoom in.

(F) If there is no value smaller than the objective function value O ₀ in the initial setting among the objective function values O _{1 to} O ₆ at each mesh point, the process proceeds to step S107. In step S107, the mesh size changing means 425 of the adjusting device 42, the K _j as K _j-1 /1.4, reducing the mesh size in multiples of 1.4.

  (G) Then, in step S108, the convergence determination means 426 of the adjustment device 42 determines the convergence, and if at least one end condition is satisfied, the process ends. Normally, the end condition may be when the mesh size is within the allowable error range. If the end condition is not satisfied, the process returns to step S102 to create a mesh point.

In general, a received signal often includes a desired wave and a delayed wave. For example, if there is a delay wave when receiving FM broadcast, the constant envelope is lost, and therefore the delay wave can be removed by the CMA algorithm. When receiving terrestrial digital broadcasting, the delayed wave can be removed by maximizing the correlation between the guard interval and the copy source signal. That is, the adaptive directional receiver shown in FIG. 1 uses the direct search method to minimize the constant envelope distortion or to maximize the correlation function between the guard interval and the copy source signal Zn ₁ , Zn ₂ , Search for a set of ground reactance values for Zn ₃ .

<Performance evaluation 1>
Examples of results of performance evaluation of the adaptive directivity receiving apparatus according to the first embodiment of the present invention are shown in FIGS. Here, assuming an FM multiplexed VICS (registered trademark) reception in a multipath environment, the incident signal is a CW signal having an equal amplitude different in frequency by 50 kHz. This model simulates the generation of beats due to interference of delayed waves in a multipath environment. Assuming that the light beam is incident from the boresight direction of the aperture of the adaptive antenna, a condition for minimizing the objective function (1) was searched by the direct search method according to the flowchart shown in FIG. 5 to 6 show directivity measurement results in an anechoic chamber when the arrival direction of the first wave is fixed at 90 ° and the arrival directions of the second wave are 150 ° and 270 °, respectively. Yes. As shown in FIGS. 5 and 6, it can be seen that the main beam is formed in the direction of the desired wave and the null is formed in the direction of the interference wave.

<Performance evaluation 2>
FIG. 7 shows an example in which three rod antennas (rod antennas) are mounted on the automobile 100 as a specific example of the adaptive antenna according to the first embodiment. That is, three rod-shaped antennas (rod antennas) function as antenna elements A1 to A3, respectively, to constitute an adaptive antenna.

  FIG. 8A shows the result of a running experiment in which the adaptive directional receiving device shown in FIG. 1 is mounted on a vehicle, FM multiplex VICS (registered trademark) is received and the reception quality is investigated. Here, the aperture of the adaptive antenna is constituted by three rod antennas mounted on the automobile 100 shown in FIG. For comparison, FIG. 8B shows a result of a running experiment performed with a single monopole antenna (without directivity formation). FIG. 8 (b) shows the results of a running experiment in which all the three antennas in FIG. 7 were removed and a single antenna attached to the rear right end of the vehicle roof was used.

The black circles, hatched squares, hatched circles, black triangles, and crosses shown in FIGS. 8A and 8B indicate packet error rates at the respective measurement points.
(A) The black circle has a packet error rate of less than 15%.
(B) The hatched square has a packet error rate of 15% or more and less than 25%.
(C) The hatched circle has a packet error rate of 25% or more and less than 50%.
(D) The black triangle has a packet error rate of 50% or more and less than 75%.
(E) x indicates that the packet error rate is 75% or more,
Respectively. From FIG. 8 (a) and FIG. 8 (b), the packet error rate is remarkably higher when the adaptive directional receiver shown in FIG. 1 is mounted on the vehicle than when the single monopole antenna is mounted on the vehicle. You can see that it is improving.

<Mounting form>
In the adaptive antenna according to the first embodiment, the antenna elements A1 to A3 form an aperture. However, one excitation element as described in Patent Documents 1 to 3 and a non-excitation element that is electromagnetically coupled to the excitation element ( Unlike an adaptive antenna using a parasite element), there is no distinction between an excitation element and a non-excitation element, and each of the antenna elements A1 to A3 is an equivalent element. Since there is no distinction between the excitation element and the non-excitation element, a topology such as arranging the non-excitation element around the excitation element is unnecessary, and a plurality of antenna elements A1 to Am (m is a positive number of 2 or more). The topology of the arrangement) is arbitrary.

  In addition, the structure of the plurality of antenna elements A1 to Am includes, for example, an external antenna such as a monopole antenna or a helical antenna, a so-called inverted F antenna of a PIFA (planer inverted-F antenna) system, a bent monopole antenna, Alternatively, a built-in antenna such as a planar substrate antenna using a printed circuit board in which a planar balun is configured with a wiring pattern may be employed. That is, the antenna element is not limited to a cylindrical conductor rod, and various antenna structures including a planar antenna (such as a patch antenna) can be employed.

  Further, each of the plurality of antenna elements A1 to Am does not have to have the same structure or the same shape, and may be a combination of antennas having different structures such as a monopole antenna and a film-like antenna.

  For this reason, the adaptive antenna according to the first embodiment includes various types such as mobile phones, FM receivers, personal computers, portable information devices such as electronic notebooks and PDAs, broadcast receiving vehicle antennas, RF tag (electronic tag) readers, and the like. It is applicable to the field of

  In the following, the case of mounting on an automobile and a portable information device (mobile phone, FM receiver, personal computer, PDA) will be exemplified, but the adaptive antenna mounting form according to the first embodiment is an example of these. Of course, it is not limited to a typical mounting structure.

-Implementation example 1: Automobile-
For example, even if it is limited to the use for automobiles, in addition to a rod-shaped antenna (rod antenna), it is installed at the front end or rear end of the roof of an automobile, and is a resin-coated roof antenna, built in an A-pillar of an automobile, and made of metal By adopting any one of the antenna elements A1 to A3 as an antenna element A1 to A3 by appropriately using any one of a pillar antenna of a type that manually pulls out the antenna and a film-like glass antenna attached to a rear window or a rear side window, An automobile equipped with the adaptive antenna according to one embodiment can be provided. That is, a plurality of antenna elements A1 to A3 constituting the antenna array may be arranged by selecting at least one of the bonnet, the front or rear end of the roof, the A pillar, the rear window, or the rear side window. The antenna elements A1 to A3 may be composed of a combination of antennas having the same structure, for example, three rod antennas (rod antennas) as shown in FIG. Of the three antenna elements A1 to A3, two may have the same structure and the remaining one may have a different structure.

  At this time, similarly to those shown in FIGS. 1 to 3, the antenna elements A1 to A3, the reflected current output circuits 31 to 33, the synthesis circuit 2, the baseband signal generation circuit 1, the objective function calculation device 41, and the adjustment device 42 and the variable reactor driver 43 also need to be incorporated at the same time.

  In this case, the baseband signal generation circuit 1, the objective function calculation device 41, the adjustment device 42, the variable reactor driver 43, etc. may be mounted as dedicated circuits, respectively, such as an FM receiver or GPS or Alternatively, it may be implemented using the functions of other electronic devices. In particular, some circuits such as the objective function calculation device 41 and the adjustment device 42 do not provide dedicated hardware resources, and are inherently built in electronic devices such as FM receivers mounted on automobiles. This function may be used to drive the microprocessor with predetermined software.

-Implementation example 2: Mobile phone-
Also, as shown in FIG. 9, as the portable information device according to the first embodiment, if the antenna elements A1 to A3 are mounted on the mobile phone 200, the mobile phone mounted with the adaptive antenna according to the first embodiment. A phone 200 can be provided. That is, FIG. 9 shows an example in which rod antennas (whipped antennas) 211a to 211c, which are the first to third antenna elements A1 to A3, are mounted on a mobile phone. Or you may mount the antenna element shown in FIGS. 10-11 in a mobile telephone. FIG. 10 shows an inverted F-type antenna 212 that can be built into the mobile phone 200 as an antenna element, and FIG. 11 illustrates a substrate antenna 213 that can be adopted as the antenna element.

  The inverted F-type antenna 212 is connected to the microstrip feed line as shown in FIG. 10, and is grounded through a via hole. As shown in FIG. 11, the substrate antenna 213 has a structure in which a meandering dielectric patch having two slits is separated from a ground plane with a space layer (gap) interposed therebetween, and includes one feed point and Has short points 1 and 2.

  Using these antenna elements A1 to A3, as shown in FIGS. 1 to 3, the reflected current output circuits 31 to 33, the synthesis circuit 2, the baseband signal generation circuit 1, the objective function calculation device 41, and the adjustment device 42 and the variable reactor driver 43 are built in the mobile phone 200, the mobile phone 200 on which the adaptive antenna according to the first embodiment is mounted can be provided.

  Although not shown in the figure, the mobile phone 200 is configured to convert a radio device, an input device such as a keyboard, a display device such as a liquid crystal display (LCD), a microphone, a speaker, and an analog audio signal into a digital signal. Needless to say, a CODEC for converting a digital signal into an analog signal, a speech processing device for speech encoding / decoding of a digital speech signal, and a microprocessor for performing various signal processing and control are included.

  The baseband signal generation circuit 1, the objective function calculation device 41, the adjustment device 42, the variable reactor driver 43, and the like may be prepared by mounting a semiconductor chip in which dedicated circuits are integrated as hardware resources. The microprocessor that is partly built in the mobile phone 200 may be realized by being driven by predetermined software. The baseband signal generation circuit 1 may employ hardware resources of a wireless device that is inherently built in the mobile phone 200.

  Although the example of the antenna of a different structure was demonstrated to FIGS. 9-11, for example, the 1st-3rd antenna elements A1-A3 are good also as a whip antenna, an inverted F type antenna, and a board | substrate antenna, respectively. Theoretically, the antenna elements A1 to A3 are composed of a combination of antennas having the same structure, for example, three rod antennas (whipped antennas), and the combination can be arbitrarily combined. is there. Of the three antenna elements A1 to A3, two may have the same structure and the remaining one may have a different structure. That is, it is possible to realize a combination of three antenna elements A1 to A3 constituting an antenna array by appropriately selecting a plurality from at least one of a rod-shaped antenna, an inverted F-type antenna, and a substrate antenna.

  Furthermore, a rod-shaped antenna (whipped antenna), an inverted F-type antenna, and a substrate antenna are examples, and combinations of other types of antennas with a rod-shaped antenna (whipped antenna), an inverted-F antenna, and a substrate antenna are also possible. Of course, the antenna elements A1 to A3 can be realized.

  In any case, by mounting the adaptive directivity receiving apparatus according to the first embodiment on the mobile phone 200 as described above, radio signals with good directivity can be received even in urban areas where high-rise buildings are dense. Can make a good call.

-Implementation example 3: FM receiver-
Similarly to a mobile phone, antenna elements A1 to A3 are configured by appropriately combining a rod-shaped antenna (whipped antenna), an inverted F-type antenna, a substrate antenna, or other antennas, and further, reflected current output circuits 31 to 33 and If the synthesis circuit 2 is directly connected to a conventional FM receiver, and the objective function calculation device 41, the adjustment device 42, and the variable reactor driver 43 are incorporated in the FM receiver together with the baseband signal generation circuit 1, the first implementation is performed. The FM receiver which mounts the adaptive antenna which concerns on this form can be provided.

  At this time, the baseband signal generation circuit 1 will be inherently incorporated in the FM receiver, but the objective function calculation device 41, the adjustment device 42, and the variable reactor driver 43 are dedicated as hardware resources. These circuits may be mounted, and a part of them may be realized by driving a microprocessor in which the FM receiver is built by predetermined software. Thereby, the stable data communication of FM receiver is realizable.

-Mounting example 4: PC and PDA-
Similarly, antenna elements A1 to A3 are configured by appropriately combining rod-shaped antennas (whipped antennas), inverted F antennas, substrate antennas, or other antennas, and further, reflected current output circuits 31 to 33 and composite circuit 2 At the same time, if the baseband signal generation circuit 1, the objective function calculation device 41, the adjustment device 42, and the variable reactor driver 43 are incorporated into a laptop personal computer or PDA, the adaptive antenna according to the first embodiment can be implemented. Notebook personal computers and PDAs can be provided. The baseband signal generation circuit 1, the objective function calculation device 41, the adjustment device 42, and the variable reactor driver 43 may each be implemented with dedicated circuits as hardware resources, such as the objective function calculation device 41 and the adjustment device 42. The circuit of the unit may be realized by driving a notebook personal computer or a microprocessor built in the PDA with predetermined software. Thereby, stable data communication of a notebook personal computer or PDA can be realized.

  As described above, according to the adaptive directivity receiving apparatus according to the first embodiment of the present invention, the excitation element is arranged in the center as in the prior art, and the non-excitation is electromagnetically coupled to the center excitation element. A small antenna having a small electromagnetic coupling can be used as compared with an electronic scanning waveguide antenna in which elements are arranged in the periphery.

  In addition, it is not necessary to place antenna elements close to configure an adaptive antenna, the distance between the antenna elements can be arbitrarily set, and furthermore, it is not necessary to unify the shape of the antenna elements. Less is.

  In other words, according to the adaptive directivity receiving apparatus according to the first embodiment of the present invention, portable information such as an adaptive directivity receiving apparatus, an automobile antenna, and a mobile phone that can be easily downsized and has few restrictions on mounting. Equipment can be provided. Further, since the transmission / reception system is one system, the configuration is simple and the cost can be reduced. Furthermore, if the output of the synthesis circuit 2 is branched and connected to a conventional transceiver, the functions of the conventional transceiver can be used as they are, and an expensive phase shifter is not required.

  Further, even if the number of antenna elements of the adaptive antenna according to the first embodiment of the present invention is about 3, a high interference removal capability can be expected. Therefore, compared with a case where a large number of non-excited elements are used for the adaptive antenna, The time required for the calculation to optimize the reactance value can be shortened.

(Second Embodiment)
As shown in FIG. 12, the adaptive directivity receiving apparatus according to the second embodiment of the present invention includes first, second, and third antenna elements A1 to A3. 3 is different from FIG. 1 in that it further includes three reflected current amplitude adjustment circuits 61 to 63. That is, the first reflected current amplitude adjusting circuit 61 includes a variable attenuator and an amplifier connected in series between the first directional coupler DC ₁ of the first reflected current output circuit 31 and the synthesis circuit 2. It is a connected attenuation / amplification circuit. The first reflected current amplitude adjusting circuit 61 is further connected to the arithmetic processing circuit (DSP) 4 via a first amplitude adjusting circuit D / A converter 71. The second reflected current amplitude adjusting circuit 62 includes a variable attenuator and an amplifier connected in series between the second directional coupler DC ₂ of the second reflected current output circuit 32 and the synthesis circuit 2. It is a connected attenuation / amplification circuit. The second reflected current amplitude adjusting circuit 62 is further connected to the arithmetic processing circuit (DSP) 4 through a second amplitude adjusting circuit DA converter 72. The third reflected current amplitude adjusting circuit 63 includes a variable attenuator and an amplifier connected in series between the third directional coupler DC ₃ of the third reflected current output circuit 33 and the synthesis circuit 2. It is a connected attenuation / amplification circuit. The third reflected current amplitude adjusting circuit 63 is further connected to the arithmetic processing circuit (DSP) 4 via a third amplitude adjusting circuit DA converter 73. Others are substantially the same as those of the adaptive directivity receiving apparatus according to the first embodiment shown in FIG.

FIG. 13 is a logical block diagram for mainly explaining the contents of the arithmetic processing circuit (DSP) 4 shown in FIG. That is, FIG. 13 shows that the arithmetic processing circuit (DSP) 4 includes an objective function calculation device 41 and an adjustment device 42 as its logical configuration. Although a detailed description of the logical configuration is omitted, the adjustment device 42 uses a direct search method, a gradient method, and a sequential search method so that the input objective function (evaluation function) Q becomes an optimum value (maximum or minimum). Or search by genetic algorithm. For example, in the case of solving the optimization problem by the direct search method, the adjustment device 42, as shown in FIG. 3, includes the initial setting means 421, the mesh creation means 422, the polling means 423, the optimum value / polling result comparison means 424, A mesh size changing unit 425 and a convergence determining unit 426 are provided. The reflection current amplitude adjustment circuits 61 to 63 are controlled by the adjustment device 42 through the DA converters 71 to 73, respectively, and the reflection current Ir output from the reflection current output circuits 31 to 33, respectively. adjusting the amplitude of _{1 ~Ir 3.}

Specifically, as described in the first embodiment, the adjustment device 42 searches the input objective function (evaluation function) Q so as to be an optimum value (maximum or minimum), and the result is obtained. as shown in FIG. 13, it generates a control signal Sx _1, Sx _2, Sx ₃ for optimizing the value of the amplitude of the reflected current Ir ₁ ~Ir _3. The individual control signals Sx ₁ , Sx ₂ , Sx ₃ generated by the adjusting device 42 are individually output to the reflected current amplitude adjusting circuits 61 to 63 via the DA converters 71 to 73, respectively. The reflected current amplitude adjusting circuits 61 to 63 independently reduce or amplify the reflected currents Ir _{1 to} Ir _{3 so that} the amplitudes of the reflected currents Ir _{1 to} Ir ₃ become desired values according to the control signals Sx ₁ , Sx ₂ , Sx _3. The rate is adjusted, and the reflected currents Ir _{1a to} Ir _3a are output. The amplitudes of the reflected currents Ir _{1a to} Ir _3a are combined with the phase control by reactance control voltages V ₁ , V ₂ , V ₃ applied to the variable reactance circuits Zn ₁ , Zn ₂ , Zn ₃ described with reference to FIG. By controlling, the directivity characteristics of the adaptive antenna can be changed more precisely.

<Evaluation by simulation>
FIG. 14 and FIG. 15 show the results of evaluating the expected signal-to-interference and noise ratio SINR by simulation when the adaptive antenna is configured as a circular array antenna in the adaptive directional receiver according to the second embodiment. The vertical axis represents the cumulative probability distribution (CDF) of received power, and the horizontal axis represents the signal-to-interference / noise ratio SINR. Here, the incoming signal is two uncorrelated BPSK (two-phase phase shift keying) signal sequences, and the objective function is a correlation value between the reference signal and the demodulated signal, which is maximized by a direct search method.

  FIG. 14A shows the signal-to-interference / noise ratio SINR when the array radius is a half wavelength and the number m of antenna elements is changed from m = 3 to 6. FIG. As shown in FIG. 14A, even when the number of antenna elements is 3, SINR> 20 dB can be expected with a probability of 90% or more.

  FIG. 14B shows the signal-to-interference / noise ratio SINR when the array radius R is changed from R = 0.25λ to λ when the number of antenna elements m is three. As shown in FIG. 14B, SINR> 20 dB can be expected with a probability of 90% or more even when the array radius R is 0.25λ.

  FIG. 15 shows the case where the number of antenna elements m is 3, the array radius is 0.5λ, the phase of the excitation current and the amplitude of the reflected current are controlled, the amplitude of the reflected current is not controlled, and the amplitude of the reflected current Shows the signal-to-interference / noise ratio SINR. Even when the amplitude of the reflected current is not controlled, SINR> 20 dB can be expected with a probability of 80% or more. However, when the amplitude is controlled, a particularly high signal-to-interference / noise ratio SINR can be obtained.

  As described above, according to the adaptive directivity receiving apparatus according to the second embodiment of the present invention, the signal-to-interference / noise ratio SINR can be improved by controlling the amplitude of the reflected current. Others are substantially the same as those in the first embodiment, and redundant description is omitted.

(Third embodiment)
As shown in FIG. 16, the adaptive directivity receiving apparatus according to the third embodiment of the present invention includes first, second, and third antenna elements A1 to A3. 3 is different from the adaptive directivity receiving apparatus according to the first embodiment shown in FIG. 1 in that the three excitation current amplitude adjustment circuits 81 to 83 are further directly connected.

  The first excitation current amplitude adjustment circuit 81 is an amplifier connected between the first antenna element A 1 and the first reflected current output circuit 31. The first excitation current amplitude adjustment circuit 81 is connected to the arithmetic processing circuit (DSP) 4 via the first amplitude adjustment circuit DA converter 91. The second excitation current amplitude adjusting circuit 82 is an amplifier connected between the second antenna element A2 and the second reflected current output circuit 32. The second excitation current amplitude adjusting circuit 82 is connected to the arithmetic processing circuit (DSP) 4 through the second amplitude adjusting circuit D / A converter 92. On the other hand, the third excitation current amplitude adjusting circuit 83 is an amplifier connected between the third antenna element A3 and the third reflected current output circuit 33. Further, the third excitation current amplitude adjusting circuit 83 is connected to the arithmetic processing circuit (DSP) 4 via the third amplitude adjusting circuit DA converter 93. Other configurations are the same as those of the adaptive directivity receiving apparatus according to the first embodiment shown in FIG.

FIG. 17 is a logical block diagram for mainly explaining the contents of the arithmetic processing circuit (DSP) 4 shown in FIG. That is, FIG. 17 shows that the arithmetic processing circuit (DSP) 4 includes an objective function calculation device 41 and an adjustment device 42 as its logical configuration. Although a detailed description of the logical configuration is omitted, the adjustment device 42 uses a direct search method, a gradient method, and a sequential search method so that the input objective function (evaluation function) Q becomes an optimum value (maximum or minimum). Or search by genetic algorithm. For example, in the case of solving the optimization problem by the direct search method, the adjustment device 42, as shown in FIG. 3, includes the initial setting means 421, the mesh creation means 422, the polling means 423, the optimum value / polling result comparison means 424, A mesh size changing unit 425 and a convergence determining unit 426 are provided. The first, second, and third excitation current amplitude adjustment circuits 81 to 83 have their amplification factors controlled by the adjustment device 42, respectively, and the excitations that the first, second, and third antenna elements A1 to A3 output respectively. The amplitude of the currents Id _{1 to} Id ₃ is adjusted.

Specifically, as described in the first embodiment, the adjustment device 42 searches for an input objective function (evaluation function) Q so as to have an optimum value (maximum or minimum). As shown in FIG. 5, the control signals Sy ₁ , Sy ₂ , and Sy ₃ are generated as optimization signals for optimizing the amplitude values of the excitation currents Id _{1 to} Id ₃ . The individual control signals Sy ₁ , Sy ₂ and Sy ₃ generated by the adjusting device 42 are output to the first, second and third excitation current amplitude adjusting circuits 81 to 83, respectively. Then, the first, second, and third excitation current amplitude adjustment circuits 81 to 83 have the amplitudes of the excitation currents Id _{1 to} Id ₃ at desired values according to the control signals Sy ₁ , Sy ₂ , and Sy ₃ , respectively. Thus, the currents Id _{1a to} Id _3a are output independently adjusted. The currents Id _{1a to} Id _3a are output to the first, second, and third reflected current output circuits 31 to 33, respectively.

That is, by changing the amplitudes of the excitation currents Id _{1 to} Id ₃ , the amplitudes of the reflected currents Ir _{1b to} Ir _3b change, and the reactance control voltage V ₁ applied to the variable reactance circuits Zn ₁ , Zn ₂ , Zn ₃ is changed. In addition to the phase control by the control of V ₂ and V ₃ , the directivity characteristic of the adaptive antenna can be changed more precisely. When using a low-priced antenna, it is also possible to simply use a low-noise amplifier without controlling the amplitude.

In this way, the first, second, and third excitation current amplitude adjustment circuits 81 to 83 are controlled by the adjustment device 42 in their amplification factors, respectively, so that the reflected current Ir _1b to the objective function becomes an optimum value. The amplitude of Ir _3b is adjusted. By controlling the phase and amplitude of the excitation current Id ₁ ~Id ₃ under the control of the reactance control voltage _{V 1, V 2, V 3} , similarly to the adaptive directional receiver shown in FIG. 12, the signal to interference plus noise The ratio SINR can be improved. Others are substantially the same as those of the adaptive directivity receiving apparatus according to the first embodiment, and redundant description is omitted.

(Other embodiments)
As described above, the present invention has been described according to the first to third embodiments. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, as described above, in the first to third embodiments, the configuration in the case where the number of antenna elements m = 3 is shown, but a structure using a large number of four or more antenna elements may be used. .

  In the first to third embodiments, the case where a directional coupler is used in the reflected current output circuit is illustrated. However, an electron having a function equivalent to a directional coupler such as a circulator is used instead of the directional coupler. Of course, it may be replaced with a part.

  Furthermore, in the first to third embodiments, the direct search method has been mainly exemplified. The direct search method is the best because of its excellent convergence, but the present invention should not be interpreted as being limited to the direct search method. It can also be realized by adopting a method or a genetic algorithm.

  In addition, the adaptive antenna according to the first embodiment is illustratively described as being mountable on a broadcast receiving automobile antenna, an RF tag reader, a mobile phone as a portable information device, an FM receiver, a personal computer, or a PDA. However, the adaptive antennas according to the second and third embodiments are similarly applied to various fields such as mobile information devices such as mobile phones, personal computers, electronic notebooks, PDAs, automobiles, and RF tag (electronic tag) readers. Of course, it is applicable to.

  As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

It is a block diagram which shows the physical structure of the adaptive directivity receiver which concerns on the 1st Embodiment of this invention. 1 is a circuit diagram illustrating a variable reactance circuit according to a first embodiment of the invention. FIG. 2 is a logical block diagram for mainly explaining the contents of an arithmetic processing circuit (DSP) shown in FIG. 1. It is a flowchart for demonstrating the example of the control method of the adaptive antenna which concerns on the 1st Embodiment of this invention. It is a graph which shows the example of the directivity measurement result of the adaptive directivity receiver which concerns on the 1st Embodiment of this invention. It is a graph which shows the example of the directivity measurement result of the adaptive directivity receiver which concerns on the 1st Embodiment of this invention. It is a schematic diagram which shows the example of the mounting state of the adaptive antenna which concerns on the 1st Embodiment of this invention. FIG. 8A is a diagram illustrating a result of an experiment for examining reception quality by the adaptive directional receiver according to the first embodiment of the present invention, and FIG. 8B is a diagram illustrating reception by a monopole antenna. It is a figure which illustrates the result of the experiment which investigates quality. It is a schematic diagram which shows the other example of the mounting state of the adaptive antenna which concerns on the 1st Embodiment of this invention. It is a schematic diagram which shows the example of the antenna element which comprises the opening of the adaptive antenna which concerns on the 1st Embodiment of this invention. It is a schematic diagram which shows the other example of the antenna element which comprises the opening of the adaptive antenna which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the structure of the adaptive directivity receiver which concerns on the 2nd Embodiment of this invention. FIG. 13 is a logical block diagram for mainly explaining the contents of an arithmetic processing circuit (DSP) shown in FIG. 12. FIG. 14A is a diagram showing the probability of the signal-to-interference noise ratio SINR that can be expected when the number of antennas constituting the aperture of the adaptive antenna according to the second embodiment of the present invention is changed. (B) is a figure which shows the probability of signal-to-interference noise ratio SINR at the time of changing an array radius. It is a figure which shows the probability of signal-to-interference noise ratio SINR which can be anticipated by the presence or absence of control of the reflected current amplitude of the adaptive directivity receiver which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the adaptive directivity receiver which concerns on the 3rd Embodiment of this invention. FIG. 17 is a logical block diagram for mainly explaining the contents of an arithmetic processing circuit (DSP) shown in FIG. 16.

Explanation of symbols

A1 to A3 ... antenna element 1 ... baseband signal generation circuit 2 ... synthesis circuit 4 ... arithmetic processing circuit (DSP)
DESCRIPTION OF SYMBOLS 11 ... Low noise amplifier 12 ... Mixer 13 ... IF filter 14 ... AGC amplifier 15 ... Demodulator 17 ... AD converter 18 ... Local oscillator 31-33 ... Reflected current output circuit 41 ... Objective function calculation device 42 ... Adjustment device 43 ... variable reactor driver 61-63 ... reflected current amplitude adjusting circuit 81-83 ... excitation current amplitude adjusting circuit 421 ... initial setting means 422 ... mesh creating means 423 ... polling means 424 ... optimal value / polling result comparing means 425 ... mesh size change Means 426: Convergence determining means

Claims (5)

A plurality of antenna elements constituting an antenna array;
A plurality of reflected current output circuits each having a load for adjusting a ground reactance of each of the plurality of antenna elements and outputting a reflected current from the load;
A combined circuit for generating a combined signal by vector combining the reflected currents output by the plurality of reflected current output circuits;
A baseband signal generation circuit for generating a demodulated signal from the combined signal;
An arithmetic processing circuit that obtains an objective function from the demodulated signal and controls each of the load values so that the objective function becomes an optimum value, and controls the directivity of the antenna array by controlling the load value An adaptive directional receiver characterized in that: Each of the plurality of reflected current output circuits is connected to a reflected current amplitude adjusting circuit that adjusts the amplitude of the reflected current output from each of the plurality of reflected current output circuits.
The reflected currents are respectively input to the synthesis circuit via the reflected current amplitude adjusting circuit, and the reflected current amplitude adjusting circuits are controlled by the arithmetic processing circuit to adjust the amplitude of the reflected current. The adaptive directivity receiver according to claim 1. Each of the plurality of antenna elements is connected to an excitation current amplitude adjusting circuit that adjusts the amplitude of the excitation current output from each of the plurality of antenna elements.
The excitation current is input to each of the plurality of reflected current output circuits via the excitation current amplitude adjustment circuit, and each of the excitation current amplitude adjustment circuits is controlled by the arithmetic processing circuit to control the amplitude of the excitation current. The adaptive directivity receiving apparatus according to claim 1, wherein adjustment is performed. A plurality of antenna elements that are arranged in at least one of a bonnet, a front end or rear end of a roof, an A pillar, or a rear window or a rear side window, and constitute an antenna array;
A plurality of reflected current output circuits each having a load for adjusting a ground reactance of each of the plurality of antenna elements and outputting a reflected current from the load;
A combined circuit for generating a combined signal by vector combining the reflected currents output by the plurality of reflected current output circuits;
A baseband signal generation circuit for generating a demodulated signal from the combined signal;
An arithmetic processing circuit that obtains an objective function from the demodulated signal and controls each of the load values so that the objective function becomes an optimum value, and controls the directivity of the antenna array by controlling the load value A vehicle equipped with a receiver for wireless communication. A plurality of antenna elements constituting an antenna array by selecting a plurality from at least one of a rod-shaped antenna, an inverted F-type antenna, and a substrate antenna;
A plurality of reflected current output circuits each having a load for adjusting a ground reactance of each of the plurality of antenna elements and outputting a reflected current from the load;
A combined circuit for generating a combined signal by vector combining the reflected currents output by the plurality of reflected current output circuits;
A baseband signal generation circuit for generating a demodulated signal from the combined signal;
An arithmetic processing circuit that obtains an objective function from the demodulated signal and controls each of the load values so that the objective function becomes an optimum value, and controls the directivity of the antenna array by controlling the load value To perform wireless communication.

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