WO2012002025A1 - Dispositif d'antenne accordable - Google Patents

Dispositif d'antenne accordable Download PDF

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Publication number
WO2012002025A1
WO2012002025A1 PCT/JP2011/059341 JP2011059341W WO2012002025A1 WO 2012002025 A1 WO2012002025 A1 WO 2012002025A1 JP 2011059341 W JP2011059341 W JP 2011059341W WO 2012002025 A1 WO2012002025 A1 WO 2012002025A1
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WIPO (PCT)
Prior art keywords
antenna device
tunable antenna
gain
frequency
loading coil
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Application number
PCT/JP2011/059341
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English (en)
Japanese (ja)
Inventor
常夫 江原
隆英 中島
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日本アンテナ株式会社
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Publication of WO2012002025A1 publication Critical patent/WO2012002025A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/50—Structural association of antennas with earthing switches, lead-in devices or lightning protectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
    • H01Q5/50—Feeding or matching arrangements for broad-band or multi-band operation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
    • H01Q9/04—Resonant antennas
    • H01Q9/06—Details
    • H01Q9/14—Length of element or elements adjustable
    • H01Q9/145—Length of element or elements adjustable by varying the electrical length
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
    • H01Q9/04—Resonant antennas
    • H01Q9/30—Resonant antennas with feed to end of elongated active element, e.g. unipole

Definitions

  • the present invention relates to a tunable antenna device capable of securing antenna gain while being a miniaturized and narrowed antenna.
  • FIG. 39 shows a general equivalent circuit diagram of the miniaturized and low-profile antenna and the glass antenna whose layout is narrowed.
  • the antenna 39 includes an antenna 110 composed of a rod antenna with a reduced size and a reduced profile and a glass antenna with a narrowed layout, and the received signal received by the antenna 110 is output It is output from the terminal OUT.
  • the frequency characteristic of the impedance of the antenna device 100 is shown in the Smith chart shown in FIG. Referring to the Smith chart shown in FIG. 40, high impedance is shown in the 76 MHz-83 MHz-90 MHz band, which is the FM radio broadcast band shown by markers 1, 2 and 3, and it is difficult to extract sufficient performance. It is understood that This is because the size of the antenna device 100 and the shape such as the vehicle design, the visibility and the mounting position are limited.
  • an antenna device for a vehicle has conventionally been proposed in which an antenna substrate on which an antenna pattern is formed is erected and disposed inside an antenna case projecting at a height of 70 mm or less from the vehicle.
  • an amplifier substrate for amplifying a received signal output from the antenna substrate is accommodated in the antenna case, and the antenna pattern is provided in the broadcasting band of the FM radio between the antenna pattern and the feeding point on the antenna substrate.
  • An antenna coil for resonance is inserted.
  • the low-profile antenna pattern which is about 1/20 the length of the FM broadcast wavelength, resonates in the FM radio broadcast band.
  • the frequency characteristic of the impedance of the antenna device 101 is shown in the Smith chart shown in FIG. Referring to the Smith chart shown in FIG. 42, high impedance is shown in the vicinity of 76 MHz and 90 MHz which are considered as band edges of the broadcast band of FM radio, but low impedance is shown in the vicinity of 83 MHz of the center frequency. . Also, the antenna device 101 resonates in the vicinity of 83 MHz. Thus, although the antenna 110 alone does not resonate in the frequency band of the FM broadcast as shown in FIG. 40, by connecting the loading coil 111 in series with the antenna 110, it is possible to resonate in the frequency band of the FM broadcast become.
  • FIG. 43 shows an equivalent circuit diagram of a conventional tunable antenna device 102 that can be tuned to a frequency within the frequency band of FM broadcasting.
  • a tunable antenna device 102 shown in FIG. 43 includes a small antenna 110 and a loading coil 111-1 connected in series to the antenna 110 and having a different number of turns, and includes a loading coil 111-1 and an output terminal OUT.
  • the tuning circuit 112 is connected between them. The received signal received by the antenna 110 is output from the output terminal OUT through the tuning circuit 112.
  • the tuning circuit 112 includes two varicap diodes BD101 and BD102 connected in series in reverse polarity to the tuning coil 112a, and the positive terminal is connected to the junction of the varicap diodes BD101 and BD102 whose cathodes are connected via a resistor R100. A voltage Vt is applied. Further, a choke coil CH100 is connected between the output terminal OUT and the ground to block a high frequency (RF) signal and to ground the output terminal OUT in a DC manner. The anodes of the varicap diodes BD101 and BD102 are DC-grounded by the choke coil CH100.
  • the reverse voltage applied between the cathode and the anode of the varicap diodes BD101 and BD102 is increased, and the capacitance value of the varicap diodes BD101 and BD102 is obtained.
  • the positive voltage Vt in the tuning circuit 112 is lowered, the reverse voltage applied between the cathode and the anode of the varicap diodes BD101 and BD102 is reduced, and the capacitance value of the varicap diodes BD101 and BD102 is increased.
  • FIG. 44 a Smith chart showing the frequency characteristics of the impedance of the tunable antenna device 102 when adjusting the positive voltage Vt to make the resonant frequency of the tunable antenna device 102 about 76 MHz is shown in FIG.
  • the impedance is low in resonance approximately at 76 MHz which is the low band edge of the broadcast band of the FM radio indicated by the marker 1.
  • FIG. 46 shows a Smith chart showing the frequency characteristics of the impedance of the tunable antenna device 102 when the resonant frequency of the tunable antenna device 102 is adjusted to about 83 MHz by adjusting the positive voltage Vt.
  • the impedance is low in resonance approximately at 83 MHz, which is the center frequency of the broadcast band of the FM radio indicated by the marker 2.
  • FIG. 46 shows a Smith chart showing the frequency characteristics of the impedance of the tunable antenna device 102 when adjusting the positive voltage Vt to make the resonant frequency of the tunable antenna device 102 about 90 MHz.
  • the impedance is low in resonance approximately at 90 MHz, which is the high band edge of the broadcast band of the FM radio indicated by the marker 3.
  • the resonant frequency of the tunable antenna device 102 is increased to about 76 MHz, which is the low band edge of the broadcast band of FM radio, and about 83 MHz, which is the center frequency. 47 to 49 by comparing the frequency characteristics of the gain of the tunable antenna device 102 when the band edge is about 90 MHz with the frequency characteristics of the gain of the antenna device 101 shown in FIG. 41 where the tuning circuit 112 is omitted. Shown in.
  • FIG. 47 shows the case where the resonant frequency of the tunable antenna device 102 is about 76 MHz, and the gain of the tunable antenna device 102 shown by the marker 1 is about 2.5 dB as compared to the gain of the antenna device 101 not provided with the tuning circuit 112. It turns out that it becomes high.
  • FIG. 48 shows the case where the resonant frequency of the tunable antenna device 102 is about 83 MHz, and the gain of the tunable antenna device 102 indicated by the marker 2 is almost equal to the gain of the antenna device 101 not provided with the tuning circuit 112. It turns out that it becomes.
  • FIG. 49 shows the case where the resonant frequency of the tunable antenna device 102 is about 90 MHz, and the gain of the tunable antenna device 102 indicated by the marker 3 is about 4 as compared with the gain of the antenna device 101 not provided with the tuning circuit 112. It turns out that it is 2 dB higher.
  • the tuning circuit 112 and adjusting the positive voltage Vt applied to the tuning circuit 112 it is possible to obtain peak gain in the entire band of the FM broadcast, and gain in the broadcast band of the FM radio Can be flattened.
  • the tunable antenna device including the tuning circuit can improve the frequency characteristics of the gain, but the varicap diode forming the tuning circuit is distorted in the received signal under a strong electric field. There was a problem of causing Therefore, it is an object of the present invention to provide a tunable antenna device which secures a gain while being a miniaturized and narrowed area antenna and in which distortion does not occur under a strong electric field.
  • the tunable antenna device comprises a small antenna that does not resonate in a used frequency band alone, a loading coil connected in series to the antenna, and A tuning circuit capable of varying impedance connected between the loading coil and the output terminal; and an AGC circuit provided between a connection point between the loading coil and the tuning circuit and the ground.
  • the antenna in which the loading coil is connected in series can be resonated at a specific frequency in a used frequency band by varying the impedance of the tuning circuit, and the impedance viewed from the AGC circuit from the AGC circuit is The most important feature is that it is within about 4% of the impedance of the AGC circuit.
  • a loading coil and a tuning circuit capable of varying tuning can be provided as a miniaturized / narrowed antenna which does not resonate in the used frequency band alone, and the antenna side is viewed from the AGC circuit Since the impedance is within about 4% of the impedance of the AGC circuit, a sufficient gain can be secured. Further, by providing the AGC circuit, it is possible to prevent the occurrence of distortion under a strong electric field.
  • FIG. 1 A circuit diagram of the configuration of the tunable antenna device of the first embodiment of the present invention is shown in FIG.
  • the tunable antenna device 1 according to the first embodiment shown in FIG. 1 is connected in series in order to resonate the antenna 10 with the frequency of the FM broadcast and the small antenna 10 which does not resonate in the broadcast band of the FM radio when the antenna alone is used.
  • a loading coil 11 and a tuning circuit 12 connected between the loading coil 11 and the output terminal OUT are provided.
  • an AGC circuit 13 is connected between the connection point of the loading coil 11 and the tuning circuit 12 and the ground. The received signal received by the tunable antenna device 1 is output from the output terminal OUT.
  • the tuning circuit 12 includes two varicap diodes BD1 and BD2 connected in series in reverse polarity to the tuning coil 12a, and the junction between the varicap diodes BD1 and BD2 whose cathodes are connected is positive via a resistor R1. A voltage Vt is applied. Further, a choke coil CH1 is connected between the output terminal OUT and the ground to block a high frequency (RF) signal and to ground the output terminal OUT in a DC manner. The anodes of the varicap diodes BD1 and BD2 are DC-grounded by the choke coil CH1. Thus, the capacitance of the varicap diodes BD1 and BD2 can be varied by changing the value of the positive voltage Vt.
  • the inductance value of the tuning coil 12a in the tuning circuit 12 and the variable capacitance range of the varicap diodes BD1 and BD2 are selected such that the tunable antenna device 1 resonates at least in the 76 MHz to 90 MHz broadcast band of FM radio. ing.
  • the positive voltage Vt is increased in the tuning circuit 12
  • the reverse voltage applied between the cathode and the anode of the varicap diodes BD1 and BD2 is increased, and the capacitance value of the varicap diodes BD1 and BD2 is reduced.
  • the resonant frequency of the tunable antenna device 1 as a whole becomes high.
  • the positive voltage Vt in the tuning circuit 12 when the positive voltage Vt in the tuning circuit 12 is lowered, the reverse voltage applied between the cathode and the anode of the varicap diodes BD1 and BD2 is reduced, and the capacitance value of the varicap diodes BD1 and BD2 is increased. Thus, the resonant frequency of the tunable antenna device 1 as a whole is lowered. In this manner, by adjusting the value of the positive voltage Vt in the tuning circuit 12, the impedance of the tuning circuit 12 is varied, so that the resonant frequency of the entire tunable antenna device 1 becomes a specific frequency within the broadcast band of the FM radio. Become tuned.
  • the AGC circuit 13 connected between the connection point of the loading coil 11 and the tuning circuit 12 and the ground does not generate distortion in the received signal due to non-linearity of the varicap diodes BD1 and BD2 under a strong electric field. Control is performed to attenuate the reception signal input to the varicap diodes BD1 and BD2 under a strong electric field.
  • a circuit example of this AGC circuit 13 is shown in FIG. 2, but the AGC circuit 13 shown in FIG. 2 comprises a control circuit 13a and two pin diodes PIN1 and PIN2 connected in series so as to be in the forward direction.
  • the cathode of the pin diode PIN2 is grounded, and the anode of the pin diode PIN1 is grounded at a high frequency by the bypass capacitor C2.
  • a connection point between the cathode of the pin diode PIN1 and the anode of the PIN diode PIN2 connected in series is connected to the connection point between the loading coil 11 and the tuning circuit 12 via the capacitor C1.
  • the AGC circuit 13 performs level control so that the level of the reception signal output to the output terminal OUT does not exceed a predetermined value. That is, the reception signal from the output terminal OUT is input to the control circuit 13a, and the control circuit 13a outputs a control signal of a DC voltage value corresponding to the level of the input reception signal.
  • the control signal is applied between the series circuit of the pin diodes PIN1 and PIN2 and the ground, and the resistance value of the pin diodes PIN1 and PIN2 connected in series can be varied according to the DC voltage value of the control signal.
  • the DC voltage value output from control circuit 13a is increased under a strong electric field, and the resistance values of pin diodes PIN1 and PIN2 are reduced. Therefore, the received signal is a capacitor C1-pin diode PIN1-bypass capacitor C2. Attenuation occurs in the path of ground and in the path of capacitor C1-pin diode PIN2-ground. Thereby, the AGC circuit 13 performs level control so that the level of the reception signal input to the varicap diodes BD1 and BD2 does not exceed a predetermined value.
  • the DC voltage value output from the control circuit 13a decreases, and the resistance values of the pin diodes PIN1 and PIN2 increase, so that the received signal is not substantially attenuated in the above path.
  • the varicap diodes BD1 and BD2 it is possible to prevent the varicap diodes BD1 and BD2 from giving distortion to the reception signal under a strong electric field by providing the AGC circuit 13. Become.
  • the resonance frequency of the tunable antenna device 1 is adjusted to about 76 MHz which is the low band edge of the broadcast band of the FM radio by adjusting the positive voltage Vt applied to the tuning circuit 12
  • the frequency characteristic of the gain of the tunable antenna device 1 of the first embodiment when the frequency is about 83 MHz and the high band edge is about 90 MHz, and the conventional antenna device 101 shown in FIG. 41 without the tuning circuit 12 3 to 5 in comparison with the frequency characteristic of the gain of.
  • FIG. 3 shows the case where the resonance frequency of the tunable antenna device 1 is about 76 MHz by adjusting the positive voltage Vt.
  • the gain of the tunable antenna device 1 of the first embodiment shown by the marker 1 is It can be seen that the gain of the conventional antenna device 101 is about 2.4 dB higher.
  • FIG. 4 is a case where the resonance frequency of the tunable antenna device 1 is adjusted to about 83 MHz by adjusting the positive voltage Vt. Referring to FIG. 4, the gain of the tunable antenna device 1 at 83 MHz indicated by the marker 2 is It can be seen that the gain is about 1.0 dB lower than the gain of the conventional antenna device 101.
  • FIG. 5 shows the case where the resonant frequency of the tunable antenna device 1 is adjusted to about 90 MHz by adjusting the positive voltage Vt.
  • the tunable antenna device of the first embodiment at 90 MHz indicated by the marker 3 It can be seen that the gain of 1 is about 1.3 dB higher than the gain of the conventional antenna device 101.
  • “Ref 1” in FIGS. 3 to 5 is a fixed first reference value, and the same applies to the subsequent figures.
  • the impedance of the measurement system is 75 ⁇ , and the same applies to the subsequent drawings.
  • the tunable antenna device 1 of the first embodiment is provided with the AGC circuit 13 to prevent the occurrence of distortion
  • the gain is slightly reduced in the broadcast band of the FM radio because the AGC circuit 13 is provided. You will come to However, the frequency characteristic of the gain in the broadcast band of FM radio is flattened.
  • FIG. 6 is a circuit diagram showing a configuration of a tunable antenna device 2 according to a second embodiment of the present invention provided with an AGC circuit 13 'modified to minimize a decrease in gain in the AGC circuit 13.
  • the tunable antenna device 2 of the second embodiment shown in FIG. 6 is different only in the configuration of the AGC circuit 13 ', and the other configuration is the same. Therefore, only the AGC circuit 13' will be described.
  • the reception signal supplied from the antenna 10 to the tuning circuit 12 is the reception signal generated at both ends of the AGC circuit 13. This reception signal is divided by the impedance of the AGC circuit 13 and the impedance seen from the AGC circuit 13 to the antenna 10 side.
  • the impedance of the AGC circuit 13 is low, the reception signal divided by that amount will be lost.
  • the impedance of the two pin diodes PIN1 and PIN2 at the off time was about 2.5 k ⁇ .
  • the AGC circuit 13 'in the tunable antenna device 2 of the second embodiment is changed to use a pin diode that exhibits a high impedance of about 5 k ⁇ when it is off. doing.
  • the resonance frequency of the tunable antenna device 2 is adjusted to about 76 MHz, which is the low band edge of the FM radio broadcast band, by adjusting the positive voltage Vt applied to the tuning circuit 12
  • the frequency characteristic of the gain of the tunable antenna device 2 of the second embodiment when the frequency is about 83 MHz and the high band edge is about 90 MHz, and the conventional antenna device 101 shown in FIG. 41 without the tuning circuit 12 7 to 9 in comparison with the frequency characteristic of the gain of.
  • FIG. 7 shows the case where the resonance frequency of the tunable antenna device 2 is adjusted to about 76 MHz by adjusting the positive voltage Vt.
  • FIG. 7 shows a case where the resonant frequency of the tunable antenna device 2 is adjusted to about 83 MHz by adjusting the positive voltage Vt.
  • the gain of the tunable antenna device 2 at 83 MHz indicated by the marker 2 is It can be seen that the gain of the conventional antenna device 101 is about 0.5 dB lower.
  • FIG. 9 shows the case where the resonant frequency of the tunable antenna device 2 is adjusted to about 90 MHz by adjusting the positive voltage Vt.
  • the tunable antenna device of the second embodiment at 90 MHz indicated by the marker 3 It can be seen that the gain of 2 is about 2.6 dB higher than the gain of the conventional antenna device 101.
  • the tunable antenna device 2 of the second embodiment can prevent the occurrence of distortion by providing the AGC circuit 13 ', and can reduce the gain in the broadcast band of the FM radio by the AGC circuit 13'. It will be possible to suppress. Also, the frequency characteristic of the gain in the broadcast band of the FM radio is flattened.
  • the degree of improvement of the gain is low from the mid band to the high band in the broadcasting band of the FM radio. Therefore, in order to investigate this cause, as shown in FIG. 10, the tuning circuit 12 and subsequent sections are separated, and the frequency characteristics of the impedance at the separated point A are examined.
  • the frequency characteristics of the impedance viewed from the point A are shown in FIG. 11.
  • the antenna impedance at 83 MHz indicated by the marker 2 is about 157 ⁇ .
  • the impedance of the AGC circuit 13 ' is about 5 k ⁇ as described above, and the antenna impedance of about 157 ⁇ is about 3.14% of about 5 k ⁇ .
  • the fact that the antenna impedance is 3% or more of the impedance of the AGC circuit 13 ' is considered to cause about 0.5 dB of gain attenuation at 83 MHz.
  • the reason for this gain attenuation is that the reception signal supplied to the tuning circuit 12 is a reception signal generated at both ends of the AGC circuit 13 ′, and this reception signal is the impedance of the AGC circuit 13 ′ and the antenna circuit 10 from the AGC circuit 13 ′. This is because the received signal is divided by the impedance viewed from the side.
  • FIG. 12 shows frequency characteristics of impedance as viewed from point A in FIG. 10 when the number of turns is reduced so as to lower the inductance value of the loading coil 11 and the inductance value of the loading coil 11 is slightly reduced.
  • the maximum impedance in the band from 76 MHz indicated by marker 1 to 90 MHz indicated by marker 3 is about 120 ⁇ .
  • the antenna impedance (120 ⁇ ) in the broadcast band of the FM radio with respect to the impedance (about 5 k ⁇ ) of the AGC circuit 13 ′ becomes 2.4% and 3% at maximum, and from the middle band of the tunable antenna device It is possible to improve the gain in the high region.
  • FIG. 1 A circuit diagram showing a configuration of a tunable antenna device 3 according to a third embodiment of the present invention for improving the gain in the middle to high frequencies based on the above result is shown in FIG.
  • the number of turns of the first loading coil 11-1 connected to the antenna 10 is reduced to reduce the inductance value so that the gain can be improved in the middle to high regions.
  • the second loading coil 11-2 is connected in series to the first loading coil 11-1 in order to compensate for the reduction in the inductance value of the first loading coil 11-1.
  • the antenna 10 resonates in the broadcast band of the FM radio by the action of the second loading coil 11-2.
  • an AGC circuit 13 ' having an impedance of about 5 k ⁇ is connected between the connection point of the first loading coil 11-1 and the second loading coil 11-2 and the ground.
  • the tuning circuit 12 is connected between the second loading coil 11-2 and the output terminal OUT, and the reception signal of the tunable antenna device 3 is output from the output terminal OUT.
  • FIG. 14 shows the frequency characteristic of the impedance of the tunable antenna device 3 of the third embodiment when the resonant frequency of the tunable antenna device 3 is set to about 76 MHz by adjusting the positive voltage Vt applied to the tuning circuit 12 .
  • the Smith chart shown in FIG. 14 it can be seen that, as indicated by the marker 1, it has a low impedance by resonating approximately at 76 MHz which is the low band edge of the broadcast band of the FM radio.
  • FIG. 15 shows the frequency characteristics of the impedance of the tunable antenna device 3 of the third embodiment when the resonant frequency of the tunable antenna device 3 is adjusted to about 83 MHz by adjusting the positive voltage Vt.
  • the Smith chart shown in FIG. 15 it can be seen that, as shown by the marker 2, it has a low impedance by resonating approximately at 83 MHz which is the center frequency of the broadcast band of the FM radio.
  • FIG. 16 is a frequency characteristic of the impedance of the tunable antenna device 3 of the third embodiment when the resonant frequency of the tunable antenna device 3 is adjusted to about 90 MHz by adjusting the positive voltage Vt.
  • the impedance is low resonance by resonating substantially at 90 MHz, which is the high band edge of the broadcast band of the FM radio.
  • the resonant voltage of the tunable antenna device 3 is adjusted to a low band edge of the broadcast band of the FM radio by adjusting the positive voltage Vt applied to the tuning circuit 12.
  • the frequency characteristics of the gain of the antenna device 101 are shown in contrast in FIGS. 17 to 19.
  • FIG. 17 shows the case where the resonant frequency of the tunable antenna device 3 is 76 MHz by adjusting the positive voltage Vt.
  • the tunable antenna device 3 of the third embodiment at 76 MHz indicated by the marker 1 is shown. It can be seen that the gain is about 2.2 dB higher than the gain of the conventional antenna device 101.
  • 18 shows the case where the resonant frequency of the tunable antenna device 3 is 83 MHz by adjusting the positive voltage Vt. Referring to FIG. 18, the tunable antenna device 3 of the third embodiment at 83 MHz indicated by the marker 2 is shown. It can be seen that the gain of V is approximately equal to the gain of the conventional antenna device 101.
  • FIG. 19 shows the case where the resonance frequency of the tunable antenna device 3 is 90 MHz by adjusting the positive voltage Vt.
  • the tunable antenna device 3 of the third embodiment at 90 MHz indicated by the marker 3 is shown. It can be seen that the gain of is approximately 3.9 dB higher than the gain of the conventional antenna device 101.
  • the tunable antenna device 3 of the third embodiment can prevent the occurrence of distortion by providing the AGC circuit 13 '.
  • the loading coil is divided into two loading coils 11-1 and 11-2, and an AGC circuit 13 'is connected between the connection point of the two loading coils 11-1 and 11-2 and the ground.
  • the mid-to-high band gain in the FM radio broadcast band can be improved to further flatten the frequency characteristic of the gain in the FM radio broadcast band.
  • the positive voltage Vt applied to the tuning circuit 12 is adjusted to set the resonance frequency of the tuning circuit 12 to about 76 MHz, which is the low band edge of the FM radio broadcast band.
  • the AGC circuit 13 ' is operating when the center frequency is about 83 MHz and the high band edge is about 90 MHz, and when the AGC circuit 13' is not operating (the pin diodes PIN1 and PIN2 are off and non-operating)
  • FIGS. FIG. 20 shows the case where the resonance frequency of the tunable antenna device 3 is 76 MHz by adjusting the positive voltage Vt.
  • FIG. 21 shows the case where the resonance frequency of the tunable antenna device 3 is 83 MHz by adjusting the positive voltage Vt. Referring to FIG. 21, the tunable antenna device 3 of the third embodiment at 83 MHz indicated by the marker 2. The gain during the operation of the AGC circuit 13 'is attenuated by only about 15 dB as compared to when the AGC circuit 13' is not in operation.
  • FIG. 22 shows the case where the resonance frequency of the tunable antenna device 3 is adjusted to 90 MHz by adjusting the positive voltage Vt.
  • the gain at the time of operation of the AGC circuit 13 ' is attenuated by 40 dB or more compared to when the AGC circuit 13' is not at operation.
  • “Ref 2” in FIG. 20 to FIG. 22 is a fixed second reference value, and the same applies to the subsequent figures.
  • a sufficient amount of attenuation can not be obtained in the vicinity of 83 MHz when the AGC circuit 13 'operates, and distortion may occur under a strong electric field. .
  • the peak of the gain appears at about 83 MHz when the AGC circuit 13 'is operating, which is considered to be because the resonance frequency of the antenna 10 and the first loading coil 11-1 is near 83 MHz. Therefore, in the tunable antenna device 3 of the third embodiment, the point a1 and the point a2 shown in FIG. 23 are disconnected, and the frequency characteristic of the impedance viewed from the point a1 is examined. Then, it was confirmed that the resonant frequency of the antenna 10 and the first loading coil 11-1 was near 83 MHz. From this, the inductance value of the first loading coil 11-1 was decreased so that this resonance frequency would be outside the broadcast band of the FM radio. FIG.
  • the resonance frequency of the antenna 10 and the first loading coil 11-1 is 91.5 MHz indicated by the marker 4 and outside the broadcast band of the FM radio.
  • the configuration of the tunable antenna device 4 according to the fourth embodiment of the present invention provided with the third loading coil 11-3 in which the inductance value of the first loading coil 11-1 is adjusted to be outside the broadcast band of FM radio.
  • the tunable antenna device 4 according to the fourth embodiment shown in FIG. 25 includes a third loading coil 11-3 connected to the antenna 10 and a fourth loading coil 11 connected in series to the third loading coil 11-3. It has -4.
  • the number of turns of the third loading coil 11-3 is smaller than that of the first loading coil 11-1 and the inductance value is lowered.
  • the number of turns of the fourth loading coil 11-4 is the second loading coil 11 so as to compensate for this.
  • the inductance value is higher than -2.
  • the resonance frequency of the antenna 10 and the third loading coil 11-3 can be set outside the broadcast band of the FM radio, and the antenna 10 is in the broadcast band of the FM radio by the action of the fourth loading coil 11-4.
  • an AGC circuit 13 'having an impedance of about 5 k ⁇ is connected between the connection point of the third loading coil 11-3 and the fourth loading coil 11-4 and the ground.
  • the tuning circuit 12 is connected between the fourth loading coil 11-4 and the output terminal OUT. The received signal received by the antenna 10 is output from the output terminal OUT through the tuning circuit 12.
  • the resonant voltage of the tunable antenna device 4 is adjusted to a low band edge of the broadcast band of the FM radio by adjusting the positive voltage Vt applied to the tuning circuit 12.
  • the frequency characteristics of the gain of the antenna device 101 are shown in contrast in FIGS. 26 shows the case where the resonance frequency of the tunable antenna device 4 is 76 MHz by adjusting the positive voltage Vt.
  • the tunable antenna device 4 of the fourth embodiment at 76 MHz indicated by the marker 1 is shown. It can be seen that the gain is about 1.4 dB higher than the gain of the conventional antenna device 101.
  • 27 shows the case where the resonance frequency of the tunable antenna device 4 is 83 MHz by adjusting the positive voltage Vt. Referring to FIG. 27, the tunable antenna device 4 of the fourth embodiment at 83 MHz indicated by the marker 2 is shown. It can be seen that the gain of is approximately 0.3 dB lower than the gain of the conventional antenna device 101.
  • FIG. 28 shows the case where the resonance frequency of the tunable antenna device 4 is 90 MHz by adjusting the positive voltage Vt.
  • the tunable antenna device 4 of the fourth embodiment at 90 MHz indicated by the marker 3. It can be seen that the gain of is approximately 4.2 dB higher than the gain of the conventional antenna device 101.
  • the gain in the lower band (near 76 MHz) of the tunable antenna device 3 of the third embodiment is reduced by about 0.8 dB.
  • the cause of this is that when the inductance value of the third loading coil 11-3 is reduced, the impedance at 76 MHz shown by the marker 1 in FIG.
  • the occurrence of distortion can be prevented by the AGC circuit 13 '.
  • the inductance value of the third loading coil 11-3 and the fourth loading coil 11-4 divided into two is adjusted as described above, and the connection point between the two loading coils 11-3 and 11-4.
  • the resonant voltage of the tunable antenna device 4 is adjusted to a low band edge of the broadcast band of the FM radio by adjusting the positive voltage Vt applied to the tuning circuit 12.
  • AGC circuit 13 ' is operating at 76 MHz
  • center frequency is about 83 MHz
  • high band edge is about 90 MHz
  • FIG. 29 shows the case where the resonance frequency of the tunable antenna device 4 is adjusted to about 76 MHz by adjusting the positive voltage Vt.
  • FIG. 30 shows the case where the resonance frequency of the tunable antenna device 4 is adjusted to about 83 MHz by adjusting the positive voltage Vt.
  • the tunable of the fourth embodiment at 83 MHz.
  • the gain at the time of operation of the AGC circuit 13 ' is attenuated by about 40 dB or more as compared with the time of the non-operation of the AGC circuit 13'.
  • FIG. 31 shows the case where the resonance frequency of the tunable antenna device 4 is adjusted to about 90 MHz by adjusting the positive voltage Vt.
  • the tunable antenna device of the fourth embodiment at 90 MHz as shown by the marker 3
  • the gain at the time of operation of the AGC circuit 13 ' is attenuated by 30 dB or more at 4 compared with the time of non-operation of the AGC circuit 13'.
  • the inductance values of the third loading coil 11-3 and the fourth loading coil 11-4 divided into two are adjusted as described above.
  • a sufficient attenuation amount of at least 30 dB can be obtained in the entire band of the FM broadcast, and the occurrence of distortion under a strong electric field can be prevented.
  • FIG. 32 is a circuit diagram showing a configuration of a tunable antenna device 5 according to a fifth embodiment of the present invention.
  • the tunable antenna device 5 of the fifth embodiment shown in FIG. 32 has a configuration in which a matching circuit is added to the tunable antenna device 4 of the fourth embodiment. That is, the tunable antenna device 5 of the fifth embodiment includes a third loading coil 11-3 connected to the antenna 10 and a fourth loading coil 11-4 connected in series to the third loading coil 11-3. And have.
  • the resonance frequency of the antenna 10 and the third loading coil 11-3 can be set outside the broadcast band of the FM radio, and the antenna 10 is in the broadcast band of the FM radio by the action of the fourth loading coil 11-4. To resonate.
  • an AGC circuit 13 ' having an impedance of about 5 k ⁇ is connected between the connection point of the third loading coil 11-3 and the fourth loading coil 11-4 and the ground.
  • the tuning circuit 12 is connected between the fourth loading coil 11-4 and the output terminal OUT.
  • a matching circuit 14 composed of a matching coil is connected between the output terminal OUT and the ground, and the reception signal of the tunable antenna device 5 is output from the output terminal OUT.
  • FIG. 33 shows the frequency characteristics of the impedance of the tunable antenna device 5 of the fifth embodiment when the resonant frequency of the tunable antenna device 5 is set to about 76 MHz by adjusting the positive voltage Vt applied to the tuning circuit 12 .
  • Vt the positive voltage
  • FIG. 33 it can be seen that, as indicated by the marker 1, it resonates at 76 MHz, which is the low band edge of the broadcast band of the FM radio, and is substantially ideally impedance matched.
  • the voltage standing wave ratio (VSWR) in this case is about 1.1.
  • FIG. 34 shows the frequency characteristic of the impedance of the tunable antenna device 5 of the fifth embodiment when the resonant frequency of the tunable antenna device 5 is adjusted to about 83 MHz by adjusting the positive voltage Vt.
  • the Smith chart shown in FIG. 34 it can be seen that, as indicated by the marker 2, it resonates substantially at 83 MHz, which is the center frequency of the broadcast band of the FM radio, and is substantially impedance matched.
  • the voltage standing wave ratio (VSWR) in this case is about 1.8.
  • FIG. 35 shows the frequency characteristics of the impedance of the tunable antenna device 5 of the fifth embodiment when the resonant frequency of the tunable antenna device 5 is adjusted to about 90 MHz by adjusting the positive voltage Vt.
  • VSWR voltage standing wave ratio
  • the resonant voltage of the tunable antenna device 5 is adjusted to a low band edge of the broadcast band of the FM radio by adjusting the positive voltage Vt applied to the tuning circuit 12.
  • the frequency characteristics of the gain of the antenna device 101 are shown in FIGS. 36 to 38 in comparison. 36 shows the case where the resonance frequency of the tunable antenna device 5 is adjusted to about 76 MHz by adjusting the positive voltage Vt. Referring to FIG.
  • FIG. 37 shows the case where the resonance frequency of the tunable antenna device 5 is adjusted to 83 MHz by adjusting the positive voltage Vt.
  • the tunable antenna device 5 of the fifth example at 83 MHz shown by the marker 2 It can be seen that the gain of V is approximately 3.2 dB higher than the gain of the conventional antenna device 101.
  • FIG. 38 shows the case where the resonance frequency of the tunable antenna device 5 is 90 MHz by adjusting the positive voltage Vt.
  • the tunable antenna device 5 of the fifth embodiment at 90 MHz indicated by the marker 3
  • the gain of is approximately 6.9 dB higher than the gain of the conventional antenna device 101.
  • the tunable antenna device 5 of the fifth embodiment can achieve a gain improvement of up to 6.9 dB.
  • the gain deviation in the broadcast band of FM radio is about 2.5 dB which is the difference between the gain when tuned to 76 MHz and the gain of 90 MHz, which further flattens the frequency characteristics of the gain in the broadcast band of FM radio can do.
  • the loading coil is divided into two loading coils 11-3 and 11-4 whose inductance value is adjusted, and an AGC circuit 13 'is connected between the connection point of the two loading coils 11-3 and 11-4 and the ground.
  • the gain from the mid band to the high band in the broadcast band of the FM radio is improved.
  • the output terminal OUT can be grounded in a direct current manner by the matching circuit 14, the choke coil CH1 can be omitted.
  • the impedance of the tuning circuit is varied by adjusting the value of the positive voltage Vt applied to the tuning circuit.
  • the resonant frequency of the entire tunable antenna device in the embodiment comes to be tuned to a specific frequency within the broadcast band of the FM radio.
  • the impedance seen from the AGC circuit to the antenna side is within about 3% of the impedance of the AGC circuit. Although it is considered ideal, sufficient gain can be secured even if it is within about 4% as described above.
  • the impedance of the AGC circuit is approximately 5 k ⁇ , but the impedance is not limited to this. If it satisfies about 4% or less of the impedance of the AGC circuit, it may be less than 5 k ⁇ .
  • the AGC circuit is a circuit using two pin diodes, it is not limited to this and may be an AGC circuit using one or more pin diodes.
  • the tuning circuit is a circuit using two varicap diodes, it is not limited to this and may be a tuning circuit using one or more varicap diodes.
  • the matching circuit may be provided in the tunable antenna device of the first to fourth embodiments. When the matching circuit is provided, the choke coil CH1 that grounds the output terminal OUT in a direct current manner can be omitted. The value of the choke coil CH1 is set to a value that does not affect the resonant frequency of the tunable antenna device according to the present invention.

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  • Details Of Aerials (AREA)
  • Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)

Abstract

L'invention concerne un dispositif d'antenne accordable garantissant un gain tout en constituant une antenne miniaturisée de surface étroite pour laquelle aucune distorsion ne se produit jamais sous des champs intenses. Le dispositif (3) d'antenne accordable du troisième mode de réalisation est muni d'une première bobine (11-1) de charge reliée à une antenne (10) et d'une deuxième bobine (11-2) de charge branchée en série avec la première. De ce fait, même si la valeur d'impédance de la première bobine (11-1) de charge est abaissée, l'antenne (10) résonne dans une bande de diffusion de radio FM sous l'effet de la deuxième bobine (11-2) de charge. De plus, un circuit (13') de CAG relie un point situé entre les bobines (11-1 et 11-2) de charge et une masse. En outre, un circuit accordé (12) est branché entre la deuxième bobine (11-2) de charge et une borne de sortie (OUT), un signal reçu en provenance du dispositif (3) d'antenne accordable étant ainsi délivré à partir de la borne de sortie (OUT).
PCT/JP2011/059341 2010-06-30 2011-04-15 Dispositif d'antenne accordable WO2012002025A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2010-149611 2010-06-30
JP2010149611A JP5714248B2 (ja) 2010-06-30 2010-06-30 チューナブルアンテナ装置

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WO2012002025A1 true WO2012002025A1 (fr) 2012-01-05

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PCT/JP2011/059341 WO2012002025A1 (fr) 2010-06-30 2011-04-15 Dispositif d'antenne accordable

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JP (1) JP5714248B2 (fr)
WO (1) WO2012002025A1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02111947U (fr) * 1989-02-21 1990-09-07
JPH0548360A (ja) * 1991-08-15 1993-02-26 Chiyuunaa Kk ラジオ受信機
JPH05259770A (ja) * 1992-03-12 1993-10-08 Chiyuunaa Kk ラジオ受信機
JPH09148961A (ja) * 1995-11-21 1997-06-06 Murata Mfg Co Ltd 無線送信装置
JPH10209897A (ja) * 1997-01-20 1998-08-07 Harada Ind Co Ltd 可変同調型アンテナ装置

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02111947A (ja) * 1988-10-21 1990-04-24 Konica Corp ネガ型感光性組成物
JP4060746B2 (ja) * 2003-04-18 2008-03-12 株式会社ヨコオ 可変同調型アンテナおよびそれを用いた携帯無線機

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02111947U (fr) * 1989-02-21 1990-09-07
JPH0548360A (ja) * 1991-08-15 1993-02-26 Chiyuunaa Kk ラジオ受信機
JPH05259770A (ja) * 1992-03-12 1993-10-08 Chiyuunaa Kk ラジオ受信機
JPH09148961A (ja) * 1995-11-21 1997-06-06 Murata Mfg Co Ltd 無線送信装置
JPH10209897A (ja) * 1997-01-20 1998-08-07 Harada Ind Co Ltd 可変同調型アンテナ装置

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JP5714248B2 (ja) 2015-05-07

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