JP2007097119A - Set substrate mounted with small-sized antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna to be built in a device protected from an electromagnetic influence on near electronic circuits by transmitting inverse-phase signals to each other so as to generate null points, while arranging the antenna of comparable performance, when using it as an antenna for transmission. <P>SOLUTION: In the substrate mounted with a small-sized antenna, the small-sized antenna and electronic circuitry are mounted in proximity to each other. The antenna output terminal of the electronic circuitry is connected to the input terminal of two small-sized antennas, which are disposed so that an inverse-phase side robe of the first antenna may be generated from the second antenna so as to cancel the mutual side robe. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a substrate mounted with a small antenna, and more particularly to a technique for electromagnetically generating an attenuation region.

  In recent years, antennas built into various mobile devices using wireless communication technology have advanced, and small antennas have been adopted. However, when the antenna is built in the device, if the antenna is installed in the vicinity of the electronic circuit, a side lobe or the like is generated together with the main lobe, and the electronic circuit is affected electromagnetically. In particular, the electrical characteristics of RF (Radio Frequency) circuits, control circuits, power supply circuits, and the like may be deteriorated due to the influence of side lobes.

  For example, since the frequency driven within the set of the RF signal and the portable device is close, malfunction occurs inside the substrate due to the electromagnetic wave signal radiated from the antenna, or noise from the substrate is superimposed on the RF signal and the SN ratio is reduced. Inconvenience arises.

If the distance between the antenna and the RF circuit is short, sufficient isolation cannot be obtained, so that a positive feedback loop is formed and the amplifier oscillates.
According to Patent Document 1, two self-complementary antenna elements that are complementary to each other are combined in a state in which one antenna element is rotated 90 degrees around a predetermined direction. At the same time, by providing a feeding point for each antenna element at the overlapping position in the overlapped state, only an electric field or magnetic field component that contributes to radiation almost exists around the antenna.

  Therefore, the electric field or magnetic field component contributing to the electric field or magnetic field energy that is not radiated and is accumulated around the antenna is minimized, so that the total sum of the electric field or magnetic field component around the antenna is minimized.

  In addition, since power is supplied with a predetermined phase difference so that the electric field vector and the magnetic field vector in the predetermined direction by the mutual antenna elements are in opposite phases, the predetermined direction can be a null point in the directivity. Therefore, proposals have been made that the electric field or magnetic field component around the antenna in that direction can be made almost zero.

  According to Patent Document 2, two self-complementary planar antenna elements having the same conductor pattern that is axially symmetrical with respect to two orthogonal linear axes are arranged to face each other in a predetermined relationship. . It has been proposed that the antenna element can be operated so that only an electric field and a magnetic field component that contribute to radiation exist around the antenna element, and an electric field and a magnetic field component that do not contribute to radiation can be minimized.

  In addition, by setting a feeding point to the two antenna elements in a symmetrical relationship on the first linear axis and feeding by a predetermined feeding method, a sharp null point in the direction of the first linear axis from the antenna is obtained. Can be provided. Therefore, the electric field and magnetic field components contributing to radiation in that direction can be made zero. In addition, the electric field and magnetic field components can be further reduced in the radiation direction.

  Further, with respect to a feeding point where two self-complementary antenna elements are disposed in opposite positions, the phase of the radiated electric field of each antenna element has a predetermined phase difference that cancels the electric field. By supplying power, a null point can be provided in the direction of the first linear axis. For this reason, proposals have been made for almost zero electric and magnetic field components in that particular direction around the antenna element.

Furthermore, according to Patent Documents 1 and 2 above, there is a proposal that can minimize the adverse effects of electromagnetic waves emitted by portable communication devices on the human head without substantial performance degradation.
JP 2000-278038 A JP 2000-077933 A

  However, when an antenna component is mounted on a small package such as a chip IC, the type of antenna is limited to a chip-shaped small antenna or the like. In addition, in order to reduce the package size, it is necessary to provide a modulation / demodulation circuit, a control circuit, and the like in the vicinity of the antenna, so that one-chip implementation is efficient.

  According to the installation of antennas as shown in Patent Documents 1 and 2, it is possible to reduce unnecessary electromagnetic waves with respect to the outside world at the device level of portable devices and the like. However, it is not a configuration that considers the influence on the circuit adjacent to the chip component in the package. Further, the configuration is not such that null points are generated by canceling the influence of the side lobes of the antennas installed in the package using the side lobes of other antennas provided in the same chip.

  The present invention has been made in view of the above circumstances, and when used as a transmitting antenna, antennas having similar performance are arranged, and signals with opposite phases are transmitted to each other to generate a null point. Thus, an object of the present invention is to provide a device built-in antenna that protects against electromagnetic influences on nearby electronic circuits.

  In a small antenna-mounted substrate on which a small antenna and an electronic circuit are mounted close to each other according to one aspect of the present invention, the antenna output terminal of the electronic circuit is connected to the input terminals of the two small antennas, These antennas are arranged so as to generate side lobes opposite in phase to the side lobes of the first antenna and to eliminate the side lobes.

  In a small antenna-mounted substrate on which a small antenna and an electronic circuit are mounted close to each other according to one aspect of the present invention, the antenna output terminal of the electronic circuit is connected to the input terminals of the two small antennas, The main lobe having the opposite phase to the side lobe of the first antenna is generated from the first antenna, and the main lobe and the side lobe of the first antenna are eliminated.

  Preferably, the antenna output terminal of the electronic circuit is distributed by a distributor, one of the distributed terminals is connected to the input terminal of the first small antenna, and the other is connected to the second antenna via a phase shifter. It is good also as a structure arrange | positioned so that a side lobe of a phase opposite to the side lobe of the said 1st antenna may be generated, and a side lobe may be eliminated.

  The antenna output terminal of the electronic circuit is set to a differential output, one of the differential outputs is connected to the input terminal of the first small antenna, the other is connected to the second antenna, and the first antenna is connected to the first antenna. A configuration may be adopted in which side lobes having opposite phases to the side lobes of the antenna are generated and the side lobes are eliminated.

  Preferably, the antenna output terminal of the electronic circuit is connected to the input terminal of the first small antenna, connected from the coupler via the phase shifter to the second antenna, and the side lobe of the first antenna. The main lobe having the opposite phase to the above may be generated, and the main lobe and the side lobe may be cancelled.

  In a small antenna-mounted substrate on which a small omnidirectional antenna and an electronic circuit are mounted in close proximity, which is one aspect of the present invention, the antenna output terminal of the electronic circuit is an input terminal of two small omnidirectional antennas. The second omnidirectional antenna is configured to generate radiated power having a phase opposite to that of the first omnidirectional antenna and to cancel the radiated power between the antennas.

  Preferably, the antenna output terminal of the electronic circuit is distributed by a distributor, one of the distributed terminals is connected to the input terminal of the first omnidirectional antenna, and the other is connected to the second non-magnetic terminal via a phase shifter. A directional antenna may be connected to generate radiated power having a phase opposite to that of the first omnidirectional antenna so that the side lobes disappear.

  Preferably, the antenna output terminal of the electronic circuit is a differential output, one of the differential outputs is connected to the input terminal of the first omnidirectional antenna, and the other is connected to the second omnidirectional antenna. However, it may be arranged so as to generate radiated power having a phase opposite to that of the first omnidirectional antenna and to eliminate the radiated power between the antennas.

  With the above configuration, when used as a transmitting antenna, antennas having the same performance are arranged opposite to each other, and RF signals having opposite phases are transmitted to generate null points to electromagnetically protect each circuit.

As a method for generating an antiphase signal, an antiphase signal can be obtained by performing transmission signal processing using a differential circuit.
Further, in the case of a circuit with a single end output, an antiphase signal can be created using a phase circuit.

  According to the present invention, the influence of unnecessary radiation inside or outside the device is reduced by controlling the phase of a signal sent to each antenna so as to cancel out unnecessary radiation power of a plurality of installed antennas.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Example 1
FIG. 1 is a diagram showing a configuration example when the output of the RF circuit is single-ended. Components such as an RF circuit 2, a phase shifter 3, a distributor 4, an antenna A5 (first antenna), and an antenna B6 (second antenna) are mounted on the substrate 1 (IC package used for a mobile phone or the like). Has been. The output of the RF circuit 2 is a single-ended output, and the output is connected to the distributor 4. The output of distributor 4 is connected to antenna A5 and antenna B6, and phase shifter 3 is connected between one of the antennas and distributor 4.

  The phase shifter 3 uses a variable phase shifter or the like for phase control. For example, a lumped constant type (chip component or the like) can be used at a low frequency, and a line length or a Lange coupler can be used at a high frequency. Here, when the transmission waveform is complicated, it is necessary to adjust the delay to each antenna input through a path passing through the phase shifter 3 and a path not passing through the phase shifter 3. In order to make the delays the same at that time, for example, a passive element (L, C) filter or a delay line is used.

  Next, in operation, each antenna generates main lobes 7 and 8 and side lobes 9 of the main lobes 7 and 8 (in the figure, substantially the same side lobes). When used as a transmitting antenna, antennas with the same performance are placed facing each other, RF signals with opposite phases are transmitted to each other, and attenuation regions (such as null points) are generated by the side lobes of each circuit. Protect.

FIG. 2 shows the waveform at that time. The vertical axis of FIG. 2 shows the amplitude, and the horizontal axis shows the phase angle. The side lobe (including the back lobe) of the antenna A5 and the side lobe (including the back lobe) of the antenna B6 are inverted 180 degrees by the phase shifter. Therefore, the side lobes cancel each other, and the synthesized wave (Δ on the graph) has an amplitude of about 0.
(Example 2)
FIG. 3 is a diagram showing a configuration example when the output of the RF circuit 2 is a differential output. Components such as an RF circuit 2, an antenna A5 (first antenna), and an antenna B6 (second antenna) are mounted on the substrate 1. The outputs of the RF circuit 2 are differential outputs 10 and 11. One of the outputs (differential output 10) is connected to the antenna A5 and the other (differential output 11) is connected to the antenna B6 (the differential output is FET (transistor). Etc.) output).

  By connecting in this way, an antiphase signal can be supplied without the phase shifter 3. That is, a signal whose phase is shifted by 180 degrees can be automatically extracted. Even if the phase difference cannot be completely compensated, if the feedback from the antenna to the amplifier becomes a gain of 0 dB or less, the object of preventing abnormal oscillation can be achieved.

Next, in operation, each antenna generates main lobes 7 and 8 and side lobes 9 of the main lobes 7 and 8 (in the figure, substantially the same side lobes). When used as a transmitting antenna, antennas with the same performance are placed facing each other, RF signals with opposite phases are transmitted to each other, and attenuation regions (such as null points) are generated by the side lobes of each circuit. Protect.
(Example 3)
FIG. 4 is a diagram showing a configuration example when the directivity of the antenna is only from one side. On the substrate 1, components such as an RF circuit 2, a phase shifter 3, an antenna A5 (first antenna), an antenna B6 (second antenna), and a coupler 12 are mounted.

  The coupler 12 picks up a signal from a part of the main line, and the side lobe 9 has a small signal level with respect to the main antenna 5 having directivity. Therefore, in order to cancel the side lobe 9, the power supply to the main antenna 5 is performed. It is enough to obtain a small part of the power. Moreover, most of the transmission power can be allocated to the main antenna A5 by adopting this method.

In the case of a high-frequency circuit, a directional coupler or a hybrid is used. In the case of a low frequency, the input unit is configured by resistance voltage division.
The output of the RF circuit 2 is a single-ended output and is connected to the antenna A5. The antenna B 6 receives a signal from the coupler 12 and is supplied with a signal whose phase is inverted by the phase shifter 3.

Next, each antenna generates a main lobe 7 and a side lobe 9 during operation. In the case of this example, each circuit is electromagnetically protected by generating an attenuation region (such as a null point) so that the side lobe of the antenna A5 cancels with the main lobe of the antenna B6.
Example 4
FIG. 5A is a diagram showing sidelobe cancellation by the antenna inside the set. On the substrate 1, an RF circuit 2, a phase shifter 3, a main antenna A5 (first antenna), a disturbing antenna B6 (second antenna), a coupler 12, and the like are mounted.

Similar to the third embodiment, the side lobe 13 of the main antenna A5 is canceled by the main lobe 14 (cancellation wave) of the disturbing antenna B.
Using Example 3 described above, as shown in FIG. 5B, electromagnetic waves that affect the human body are canceled.

Also, when used as a receiving antenna, the signals are received under conditions of good signal quality by switching between them and functioning as a diversity antenna.
In addition to a small antenna, a pattern antenna (an antenna laid out on a substrate) can be applied. Alternatively, the antenna directivity is adjusted by phase synthesis so that the null point faces the noise source generated inside the set.
(Example 5)
A simulation model for confirming the effect of the above embodiment will be described. FIG. 6 shows the dimensions of the simulation model. As the pattern, a conductor corresponding to Cu (σ = 58 MS / m) was set. The substrate 71 has a relative dielectric constant (εr = 10) equivalent to alumina.

In this example, the influence of the main lobe and the side lobe does not seem to be considered, but the effect of the above embodiment is confirmed by determining the direction and power of the output radio wave.
FIG. 7A shows a case where in-phase power feeding is performed on the two antennas 72 and 73 mounted on the substrate as a simulation model. In FIG. 7B, the pattern from the input port 74 to the antenna 73 is made longer than the pattern from the antenna 72 so that the output phase difference between the antennas 72 and 73 is 180 ° (reverse phase). This is an example of a power supply model. The phase is shifted by 180 ° due to the pattern of the dotted line range 75 in FIG.

In this simulation, analysis was performed using a patch antenna to save analysis resources.
FIG. 8 shows the effect of the change in the leakage power between the antennas due to the difference in the feeding method. It is the result of having supplied electric power from the input port (Input Port) of Drawing 7 (a) and (b) to an antenna (ANT), and calculating the amount of signal leak between antennas with a probe (Probe). Actually, a circuit (RF circuit or the like) is installed around the probe.

  From FIG. 8, it is possible to reduce the amount of signal leakage between antennas by giving a phase difference to the feed power even at the same signal level. In the simulation results, it was confirmed that the leakage amount was reduced by about 10 (dB) at 4.65 to 4.85 GHz by performing the reverse phase power feeding. In the graph of the figure, the vertical axis represents the leak amount (dB) and the horizontal axis represents the frequency (GHz).

  According to the present invention, an antenna can be mounted on a transmission module (transmission / reception module) housed in a small package. Design advantages include the following. Increases the degree of freedom for mounting antennas inside small transmitters and improves transmission output.

  In addition, by applying the antiphase feed antenna structure proposed in the present invention to a small module such as a one-chip transmission IC or SIP, it is possible to reduce the leakage power between the antennas and improve the transmission output compared to the conventional one. Is possible.

  In addition, simplification and deletion of electromagnetic shields along with improved isolation enables high-density placement, resulting in advantages such as reduced loss due to shortened transmission lines, reduced external coupling, RF block separation, and high-density mounting. This improves design freedom.

In the following examples, planar antennas are used, but application to lower frequency applications is also possible by using chip type antennas using high dielectric constant and magnetic permeability materials.
(Example 6)
FIG. 9 is a diagram showing a configuration example when the output of the RF circuit 92 is single-ended and two omnidirectional antennas are used. Components such as an RF circuit 92, a phase shifter 93, a distributor 94, a first omnidirectional antenna 95, and a second omnidirectional antenna 96 are mounted on a substrate 91 (IC package used for a mobile phone or the like). Has been. The output of the RF circuit 92 is a single-ended output, and the output is connected to the distributor 94. The output of distributor 94 is connected to first omnidirectional antenna 95 and second omnidirectional antenna 96, and phase shifter 93 is connected between one of the antennas and distributor 94. .

  The phase shifter 93 uses a variable phase shifter or the like for phase control. For example, a lumped constant type (chip component or the like) can be used at a low frequency, and a line length or a Lange coupler can be used at a high frequency. Here, when the transmission waveform is complicated, it is necessary to adjust the delay to each omnidirectional antenna input by a path passing through the phase shifter 93 and a path not passing through the phase shifter 93. In order to make the delays the same at that time, for example, a passive element (L, C) filter or a delay line is used.

  Next, each omnidirectional antenna generates radiated power 97 and 98 (antiphase radiated power) in operation. When used as a transmission antenna, antennas with the same performance are placed, RF signals with opposite phases are transmitted to each other, and attenuation regions (null points, etc.) are generated by the side lobes of each circuit. To protect.

  In this way, the power distributed between the antennas is attenuated by performing the reverse phase power supply to the omnidirectional antenna having the same characteristics. As a result, leakage components to the RF circuit 92 can be suppressed. Note that the output of the RF circuit 2 may be a differential output.

  The present invention is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the gist of the present invention.

It is the figure which showed the structural example in case the output of RF circuit is a single end output. It is the figure which showed the amplitude and the phase angle. It is the figure which showed the structural example in case RF circuit output is a differential output. It is the figure which showed the example of a structure in case the directivity of an antenna is made only from one side. (A) It is the figure which showed the side lobe cancellation by the antenna inside a set. (B) It is the figure which showed the influence on a human body. It is a figure which shows the dimension of a simulation model. (A) It is a figure which shows an in-phase electric power feeding model. (B) It is a figure which shows a reverse phase electric power feeding model. It is a figure which shows the difference in the amount of leaks by the difference in the electric power feeding method. It is the figure which showed the example of a structure when the output of RF circuit is a single end output and an omnidirectional antenna is used.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Board | substrate (set board | substrates, such as a mobile phone), 2 ... RF circuit, 3 ... Phase shifter, 4 ... Distributor 5 ... Antenna A (1st antenna), 6 ... Antenna B (2nd antenna)
7 ... main lobe, 8 ... main lobe, 9 ... side lobe 10 ... differential output, 11 ... differential output, 12 ... coupler 13 ... side lobe, 14 ... main lobe (cancellation wave)
DESCRIPTION OF SYMBOLS 15 ... Communication apparatus, 16 ... Null point 71 ... Board | substrate, 72 ... Antenna, 73 ... Antenna, 74 ... Input port 91 ... Board | substrate (set board | substrates, such as a mobile phone), 92 ... RF circuit, 93 ... Phase shifter 94 ... Divider 95 ... first omnidirectional antenna 96 ... second omnidirectional antenna 97 ... radiated power 98 ... radiated power 99 ... attenuation region

Claims (8)

In a small antenna mounted board where a small antenna and an electronic circuit are mounted in close proximity,
The antenna output terminal of the electronic circuit is connected to the input terminals of the two small antennas, a side lobe having a phase opposite to that of the first antenna is generated from the second antenna, and the side lobes of each other are eliminated. A small antenna-mounted substrate characterized by being arranged as described above. In a small antenna mounted board where a small antenna and an electronic circuit are mounted in close proximity,
The antenna output terminal of the electronic circuit is connected to the input terminals of the two small antennas, a main lobe having a phase opposite to the side lobe of the first antenna is generated from the second antenna, and the main lobe and the first lobe are generated. 1. A substrate mounted with a small antenna, wherein the substrate is arranged so as to eliminate the side lobe of one antenna.   The antenna output terminal of the electronic circuit is distributed by a distributor, one of the distributed terminals is connected to the input terminal of the first antenna, the other is connected to the second antenna via a phase shifter, and the first 2. The substrate mounted with a small antenna according to claim 1, wherein the side lobes having opposite phases to the side lobes of one antenna are generated and the side lobes are eliminated.   The antenna output terminal of the electronic circuit is set to differential output, one of the differential outputs is connected to the input terminal of the first small antenna, the other is connected to the second antenna, 2. The substrate mounted with a small antenna according to claim 1, wherein the side lobes are arranged so as to generate side lobes having opposite phases to the side lobes and to eliminate the side lobes.   The antenna output terminal of the electronic circuit is connected to the input terminal of the first small antenna, is connected from the coupler to the second antenna via the phase shifter, and has a phase opposite to that of the side lobe of the first antenna. 3. The substrate mounted with a small antenna according to claim 2, wherein a lobe is generated and arranged so as to cancel out the main lobe and the side lobe. In a small antenna-mounted substrate where a small omnidirectional antenna and an electronic circuit are mounted in close proximity,
The antenna output terminal of the electronic circuit is connected to the input terminals of the two small omnidirectional antennas, and the radiated power having a phase opposite to that of the first omnidirectional antenna is obtained from the second omnidirectional antenna. A substrate mounted with a small antenna, characterized in that the substrate is arranged so as to cancel out the radiated power between the antennas.   The antenna output terminal of the electronic circuit is distributed by a distributor, one of the distributed terminals is connected to the input terminal of the first omnidirectional antenna, and the other is connected to the second omnidirectional antenna via a phase shifter. 7. The small antenna mounting according to claim 6, wherein the antenna is disposed so as to generate radiation power having a phase opposite to that of the first omnidirectional antenna and cancel radiation power between the antennas. Board.   The antenna output terminal of the electronic circuit is a differential output, one of the differential outputs is connected to the input terminal of the first omnidirectional antenna, the other is connected to the second omnidirectional antenna, The board mounted with a small antenna according to claim 6, wherein the board is arranged so as to generate radiation power having a phase opposite to that of the first omnidirectional antenna and cancel radiation power between the antennas.