JP2008092425A

JP2008092425A - High frequency glass antenna device for vehicles

Info

Publication number: JP2008092425A
Application number: JP2006272904A
Authority: JP
Inventors: Goshi Yamamoto; 剛資山本; Masateru Ito; 昌輝伊東
Original assignee: Asahi Glass Co Ltd
Current assignee: AGC Inc
Priority date: 2006-10-04
Filing date: 2006-10-04
Publication date: 2008-04-17

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high frequency glass antenna device for vehicles for improving an antenna gain. <P>SOLUTION: An energizing heating type defogger provided with many heater lines 2 and a plurality of bus bars for feeding power to the heater lines 2 is provided on a rear window glass plate 1, an antenna conductor 4 is provided in the margin part of the rear window glass plate 1 other than the area of the defogger, and choke coils 3a and 3b are respectively connected between a first bus bar 5a and a DC power source 9 and between a second bus bar 5b and the ground. The antenna conductor 4 has a function of receiving an SW broadcast band, the antenna conductor 4 and the defogger are capacitively coupled in the SW broadcast band, and the resonance frequency of resonance generated mainly by the impedance of the defogger and the impedance of two choke coils 3a and 3b does not exist in 3 to 22 MHz. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、ＳＷ放送帯（１．６１５〜３０ＭＨｚ）の内の（３〜２２ＭＨｚ）を受信するのに適する自動車用高周波ガラスアンテナ装置に関する。 The present invention relates to a high-frequency glass antenna device for automobiles suitable for receiving (3 to 22 MHz) of a SW broadcast band (1.615 to 30 MHz).

従来、ＳＷ放送の受信は、棒状アンテナで行っているのが一般的であった。また、ＡＭ放送、ＦＭ放送及びＳＷ放送を受信するアンテナシステムとしては、ＡＭ放送とＳＷ放送については棒状アンテナで受信し、ＦＭ放送については棒状アンテナとガラスアンテナとのダイバーシティ受信を行っていた。 Conventionally, SW broadcasts are generally received with a rod-shaped antenna. As an antenna system for receiving AM broadcast, FM broadcast, and SW broadcast, AM broadcast and SW broadcast are received with a rod-shaped antenna, and FM broadcast is diversity reception with a rod-shaped antenna and a glass antenna.

したがって、ＳＷ放送単独の受信システムにおいても、ＡＭ放送、ＦＭ放送及びＳＷ放送を受信するアンテナシステムにおいても、コンパクトでアンテナ性能に優れたアンテナシステムがなかった。 Therefore, neither the receiving system for SW broadcasting alone nor the antenna system for receiving AM broadcasting, FM broadcasting, or SW broadcasting has a compact and excellent antenna system.

本発明は、従来技術の有する前述の欠点を解消する自動車用高周波ガラスアンテナ装置の提供を目的とする。 An object of the present invention is to provide a high-frequency glass antenna device for automobiles that eliminates the above-mentioned drawbacks of the prior art.

本発明は、多数本のヒータ線と、該ヒータ線に給電する複数のバスバとを有する通電加熱式のデフォッガが自動車の後部窓ガラス板に設けられており、デフォッガの領域以外の、後部窓ガラス板の余白部にアンテナ導体が設けられており、一のバスバと直流電源との間に第１のチョークコイルが接続されており、他のバスバと接地との間に第２のチョークコイルが接続されている自動車用高周波ガラスアンテナ装置において、
該アンテナ導体は少なくともＳＷ放送帯を受信する機能を有しており、
該アンテナ導体とデフォガとがＳＷ放送帯では容量結合しており、
主に、デフォガのインピーダンスと、第１のチョークコイルのインピーダンスと、第２のチョークコイルのインピーダンスとで生じる共振の共振周波数が３〜２２ＭＨｚに存在しないことを特徴とする自動車用高周波ガラスアンテナ装置を提供する。 In the present invention, an electrically heated defogger having a plurality of heater wires and a plurality of bus bars for supplying electric power to the heater wires is provided on a rear window glass plate of an automobile, and a rear window glass other than the area of the defogger An antenna conductor is provided in the blank portion of the plate, the first choke coil is connected between one bus bar and the DC power source, and the second choke coil is connected between the other bus bar and the ground. In the automotive high frequency glass antenna device,
The antenna conductor has a function of receiving at least the SW broadcast band,
The antenna conductor and the defogger are capacitively coupled in the SW broadcast band,
A high-frequency glass antenna device for automobiles, characterized in that a resonance frequency of resonance generated by the impedance of the defogger, the impedance of the first choke coil, and the impedance of the second choke coil does not exist in 3 to 22 MHz. provide.

本発明では、上記構成を採るために、ＳＷ放送帯の内の放送周波数が集中している、３〜２２ＭＨｚの周波数帯域を受信する際に、３〜２２ＭＨｚの周波数帯域にわたって平坦なアンテナ利得を得ることができる。さらに、本発明では、低ノイズ、高アンテナ利得及び小スペース化に寄与する自動車用高周波ガラスアンテナ装置が得られる。 In the present invention, in order to adopt the above-described configuration, when receiving a frequency band of 3 to 22 MHz where broadcast frequencies in the SW broadcast band are concentrated, a flat antenna gain is obtained over the frequency band of 3 to 22 MHz. be able to. Furthermore, the present invention provides a high-frequency glass antenna device for automobiles that contributes to low noise, high antenna gain, and small space.

以下、本発明のアンテナ装置を添付の図面に示される好適実施形態に基づいて詳細に説明する。図１は本発明の自動車用高周波ガラスアンテナ装置の一実施形態を示す。 Hereinafter, an antenna device of the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings. FIG. 1 shows an embodiment of a high frequency glass antenna device for automobiles according to the present invention.

図１において、１は自動車の後部窓ガラス板、２はヒータ線、３ａは第１のチョークコイル、３ｂは第２のチョークコイル、４は第１のアンテナ導体、５ａは第１のバスバ、５ｂは第２のバスバ、６はフィルタ回路、６ａはコンデンサ、６ｂはコイル、７は第２のアンテナ導体、８は前置増幅器、８ａは同軸ケーブル、９は直流電源、１１は短絡線、Ｌ_Ｘは第１のアンテナ導体の最大横幅、Ｌ_Ｙは第１のアンテナ導体の最大縦幅である。 In FIG. 1, 1 is a rear window glass plate of an automobile, 2 is a heater wire, 3a is a first choke coil, 3b is a second choke coil, 4 is a first antenna conductor, 5a is a first bus bar, 5b. Is a second bus bar, 6 is a filter circuit, 6a is a capacitor, 6b is a coil, 7 is a second antenna conductor, 8 is a preamplifier, 8a is a coaxial cable, 9 is a DC power supply, 11 is a short circuit wire, L _X the maximum width of the first antenna conductor, the L _Y is the maximum vertical width of the first antenna conductor.

図１に示すとおり、本発明において、多数本のヒータ線２と、ヒータ線２に給電する複数のバスバ５ａ，５ｂとを有する通電加熱式のデフォッガが自動車の後部窓ガラス板１に設けられている。 As shown in FIG. 1, in the present invention, an electrically heated defogger having a large number of heater wires 2 and a plurality of bus bars 5a and 5b for supplying power to the heater wires 2 is provided on the rear window glass plate 1 of the automobile. Yes.

デフォッガの領域以外の、後部窓ガラス板１の余白部に第１のアンテナ導体４が設けられている。第１のバスバ５ａと直流電源との間、及び、第２のバスバ５ｂと接地との間にチョークコイル３ａ，３ｂがそれぞれ接続されている。第１のアンテナ導体４は少なくともＳＷ放送帯を受信する機能を有している。 A first antenna conductor 4 is provided in a blank portion of the rear window glass plate 1 other than the defogger region. Choke coils 3a and 3b are connected between the first bus bar 5a and the DC power source and between the second bus bar 5b and the ground, respectively. The first antenna conductor 4 has a function of receiving at least the SW broadcast band.

本発明において、第１のアンテナ導体４とデフォガとがＳＷ放送帯では容量結合している。そのため、デフォガに励起されるＳＷ放送帯の受信信号がこの容量結合により、第１のアンテナ導体４に伝送される。 In the present invention, the first antenna conductor 4 and the defogger are capacitively coupled in the SW broadcast band. Therefore, the SW broadcast band received signal excited by the defogger is transmitted to the first antenna conductor 4 by this capacitive coupling.

本発明において、主に、デフォガのインピーダンスと、第１のチョークコイル３ａのインピーダンスと、第２のチョークコイル３ｂのインピーダンスとで生じる共振の共振周波数がＳＷ放送帯の帯域内に存在しない。このようにするのは、この共振周波数の付近では、ラジオノイズの影響が大きいからである。なお、デフォガのインピーダンスは、主にデフォガの浮遊容量からなり、チョークコイル３ａ，３ｂのインピーダンスは、主にインダクタンスからなる。 In the present invention, the resonance frequency of resonance generated mainly by the impedance of the defogger, the impedance of the first choke coil 3a, and the impedance of the second choke coil 3b does not exist in the SW broadcast band. This is because the influence of radio noise is large near the resonance frequency. The impedance of the defogger is mainly composed of stray capacitance of the defogger, and the impedances of the choke coils 3a and 3b are mainly composed of inductance.

図１に示す例のように、第１のアンテナ導体４とデフォガとの間に、ＦＭ放送帯受信用の第２のアンテナ導体７が設けられている場合には、共振周波数がＳＷ放送帯とＦＭ放送帯との間に存在していることが好ましい。ＦＭ放送帯及びＳＷ放送帯において、アンテナ利得向上、及び、ラジオノイズの影響を低減するためである。 When the second antenna conductor 7 for FM broadcast band reception is provided between the first antenna conductor 4 and the defogger as in the example shown in FIG. 1, the resonance frequency is the SW broadcast band. It is preferable that it exists between FM broadcast bands. This is to improve the antenna gain and reduce the influence of radio noise in the FM broadcast band and the SW broadcast band.

チョークコイル３ａ，３ｂはそれぞれＳＷ放送帯の周波数を遮断又は減衰する機能を有することが好ましく、第２のアンテナ導体７が設けられている場合には、ＦＭ放送帯の周波数を遮断又は減衰する機能を有することが好ましい。これらの観点から、チョークコイル３ａ，３ｂのそれぞれのインダクタンス値は、０．０５μＨ以上が好ましい。より好ましい範囲は、０．１μＨ以上であり、特に好ましい範囲は、０．１５μＨ以上である。 Each of the choke coils 3a and 3b preferably has a function of blocking or attenuating the frequency of the SW broadcast band, and when the second antenna conductor 7 is provided, the function of blocking or attenuating the frequency of the FM broadcast band. It is preferable to have. From these viewpoints, the inductance value of each of the choke coils 3a and 3b is preferably 0.05 μH or more. A more preferable range is 0.1 μH or more, and a particularly preferable range is 0.15 μH or more.

第１のアンテナ導体４が複数本のアンテナエレメントを備えており、第１のアンテナ導体４が占める、後部窓ガラス板１の領域が０．０６ｍ^２以上であることが好ましい。ＡＭ放送帯のアンテナ利得を向上させるためである。 The first antenna conductor 4 includes a plurality of antenna elements, and the area of the rear window glass plate 1 occupied by the first antenna conductor 4 is preferably 0.06 m ² or more. This is to improve the antenna gain of the AM broadcast band.

図１に示す例では、第１のアンテナ導体４とデフォガとの間に、第２のアンテナ導体７が設けられている。第２のアンテナ導体７はＦＭ放送帯を受信する機能を有する。なお、第１のバスバ５ａから、ＦＭ放送波帯用サブ受信信号が同軸ケーブル８ａを経て前置増幅器８に送られている。 In the example shown in FIG. 1, a second antenna conductor 7 is provided between the first antenna conductor 4 and the defogger. The second antenna conductor 7 has a function of receiving the FM broadcast band. The FM broadcast wave band sub-received signal is sent from the first bus bar 5a to the preamplifier 8 via the coaxial cable 8a.

第１のチョークコイル３ａのインダクタンスと、第２のチョークコイル３ｂのインダクタンス値とが同一又はほぼ同一とし、チョークコイル３ａ，３ｂのインダクタンス値をそれぞれＬ_ｃとし、前記デフォガの浮遊容量をＣ_ｄとするとき、図１に示す例では、共振周波数は近似的に、（１／（２Π））・（Ｌ_ｃ・Ｃ_ｄ）^−０．５で表され、（１／（２Π））・（Ｌ_ｃ・Ｃ_ｄ）^−０．５が、２２〜５０ＭＨｚであることが、３〜２２ＭＨｚの周波数帯域にわたって平坦なアンテナ利得が得られ好ましい。 The inductance of the first choke coil 3a and the inductance value of the second choke coil 3b are the same or substantially the same, the inductance values of the choke coils 3a and 3b are L _c , respectively, and the stray capacitance of the defogger is C _d In the example shown in FIG. 1, the resonance frequency is approximately represented by (1 / (2Π)) · (L _c · C _d ) ^−0.5 , and (1 / (2Π)) · (L _c · C _d ) ^−0.5 is preferably 22 to 50 MHz because a flat antenna gain can be obtained over a frequency band of 3 to 22 MHz.

本発明において、第１のアンテナ導体４がＡＭ放送帯を受信する機能を有している場合、第１のアンテナ導体４とデフォガとが、ＡＭ放送帯では実質的に容量結合していないことが好ましい。この容量結合が実質的になされていないと、ＡＭ放送帯の受信信号がデフォガに漏れてアンテナ利得が減衰することが少ないからである。この容量結合が実質的になされていないようにするには、第１のアンテナ導体と前記デフォガとの間の間隔が３２ｍｍ以上であることが好ましい。なお、小スペース化のためには、第１のアンテナ導体とデフォガとの間の間隔を６０ｍｍ以下にすることが好ましい。 In the present invention, when the first antenna conductor 4 has a function of receiving the AM broadcast band, the first antenna conductor 4 and the defogger are not substantially capacitively coupled in the AM broadcast band. preferable. This is because, if this capacitive coupling is not substantially performed, the reception signal of the AM broadcast band leaks to the defogger and the antenna gain is hardly attenuated. In order not to make this capacitive coupling substantially, it is preferable that the distance between the first antenna conductor and the defogger is 32 mm or more. In order to reduce the space, the distance between the first antenna conductor and the defogger is preferably 60 mm or less.

第１のアンテナ導体の横幅が６３０〜１０３０ｍｍであることが好ましい。ＳＷ放送帯をフラットに受信するためである。この範囲内であると、この範囲外と比較してＳＷ放送帯をフラットに受信できる。 The lateral width of the first antenna conductor is preferably 630 to 1030 mm. This is because the SW broadcast band is received flat. Within this range, the SW broadcast band can be received flat compared to outside this range.

図１に示す例では、第２のアンテナ導体７が、３００〜５００ｍｍの導体長のエレメントであり、第１のアンテナ導体４と第２のアンテナ導体７との間の間隔が、１５〜４５ｍｍであることが好ましい。この範囲内であると、この範囲外と比較してＦＭ放送帯におけるアンテナ利得が向上する。 In the example shown in FIG. 1, the second antenna conductor 7 is an element having a conductor length of 300 to 500 mm, and the distance between the first antenna conductor 4 and the second antenna conductor 7 is 15 to 45 mm. Preferably there is. Within this range, the antenna gain in the FM broadcast band is improved compared to outside this range.

図２は図１とは別の実施例の平面図である。図２において、１１，１２，１３はＦＭ放送帯調整用のエレメント、１４はダミーパターンである。なお、図２に示す例では、ＦＭ放送帯域内で第１のアンテナ導体４と第２のアンテナ導体７とが容量結合しているため、第１のアンテナ導体４の形状及び寸法も、第２のアンテナ導体７のＦＭ放送帯のアンテナ性能に影響があるため、ＦＭ放送帯調整用のエレメント１１，１２，１３が設けられており、エレメント１１，１２，１３の形状及び寸法を改変することによりＦＭ放送帯の受信特性を調整している。なお、図２において、Ｌ_Ｘはエレメント１３を含まないものとする。 FIG. 2 is a plan view of an embodiment different from FIG. In FIG. 2, reference numerals 11, 12, and 13 denote FM broadcast band adjustment elements, and reference numeral 14 denotes a dummy pattern. In the example shown in FIG. 2, since the first antenna conductor 4 and the second antenna conductor 7 are capacitively coupled within the FM broadcast band, the shape and dimensions of the first antenna conductor 4 are also the second. Since the antenna performance of the FM antenna band of the antenna conductor 7 is affected, elements 11, 12, and 13 for adjusting the FM broadcast band are provided. By modifying the shapes and dimensions of the elements 11, 12, and 13 The reception characteristics of the FM broadcast band are adjusted. In FIG. 2, L _X does not include the element 13.

本発明において、デフォガの浮遊容量が８０〜２００ｐＦであることがアンテナ利得を向上させる点で好ましい。より好ましい範囲は、１２０〜１７０ｐＦである。 In the present invention, the stray capacitance of the defogger is preferably 80 to 200 pF from the viewpoint of improving the antenna gain. A more preferable range is 120 to 170 pF.

前置増幅器８は、ＳＷ放送帯、ＡＭ放送帯及びＦＭ放送帯の少なくとも１つの受信信号を増幅するためのものである。フィルタ回路６は電源ノイズ等を低減するためのものである。なお、前置増幅器８の出力は受信機（不図示）に送られる（図１に示す矢印）。 The preamplifier 8 is for amplifying at least one received signal in the SW broadcast band, the AM broadcast band, and the FM broadcast band. The filter circuit 6 is for reducing power supply noise and the like. The output of the preamplifier 8 is sent to a receiver (not shown) (arrow shown in FIG. 1).

図１に示す例では、複数本のヒータ線２の左右中央付近の部分が短絡線１１により短絡されている。短絡線１１はデフォガのインピーダンス調整のために設けられるもので、必要に応じて設けられる。 In the example shown in FIG. 1, the portions near the left and right centers of the plurality of heater wires 2 are short-circuited by the short-circuit wire 11. The short-circuit line 11 is provided for adjusting the impedance of the defogger, and is provided as necessary.

以下に実施例を用いて本発明を説明するが、本発明はこれらの実施例には限定されず、本発明の要旨を損なわない限り、各種の改良や変更も本発明に含まれる。 The present invention will be described below with reference to examples, but the present invention is not limited to these examples, and various improvements and modifications are also included in the present invention as long as the gist of the present invention is not impaired.

以下、図面にしたがって、実施例を詳細に説明する。自動車の後部窓ガラス板を使用し、図２に示すような自動車用高周波ガラスアンテナを製作した。図２に記載されている寸法の単位はｍｍである。各部の寸法、定数は以下のとおりである。 Hereinafter, embodiments will be described in detail with reference to the drawings. A high-frequency glass antenna for an automobile as shown in FIG. 2 was manufactured using a rear window glass plate of the automobile. The unit of the dimension described in FIG. 2 is mm. The dimensions and constants of each part are as follows.

実施例における、チョークコイル３ａ，３ｂのそれぞれのインダクタンス値が０．１μＨのデータは計算値であり、これ以外のチョークコイル３ａ，３ｂのそれぞれのインダクタンス値に関連するデータは実測値である。また、アンテナ利得の実測値は前置増幅器８の出力端における測定値である。 In the embodiment, data in which the inductance values of the choke coils 3a and 3b are 0.1 μH are calculated values, and other data related to the inductance values of the choke coils 3a and 3b are actually measured values. The actual measured value of the antenna gain is a measured value at the output terminal of the preamplifier 8.

Ｌ_ｘを８００ｍｍとして、チョークコイル３ａ，３ｂのそれぞれのインダクタンス値を０．１μＨ、０．２μＨ、０．５μＨ及び１．０μＨに変化させたときの、アンテナ利得‐周波数の特性図を図３に示した。 FIG. 3 is a characteristic diagram of antenna gain-frequency when L _x is 800 mm and the inductance values of the choke coils 3a and 3b are changed to 0.1 μH, 0.2 μH, 0.5 μH, and 1.0 μH, respectively. Indicated.

チョークコイル３ａ，３ｂのそれぞれのインダクタンス値を０．２μＨとして、Ｌ_ｘを５００ｍｍ、８００ｍｍ及び１１００ｍｍに変化させたときの、アンテナ利得‐周波数の特性図を図４に示した。 FIG. 4 shows a characteristic diagram of antenna gain-frequency when the inductance value of each of the choke coils 3a and 3b is 0.2 μH and L _x is changed to 500 mm, 800 mm, and 1100 mm.

Ｌ_ｘを８００ｍｍとし、チョークコイル３ａ，３ｂのそれぞれのインダクタンス値を０．１μＨ、０．２μＨ、０．５μＨ及び１．０μＨに変化させたときの、３〜２２ＭＨｚにおけるアンテナ利得差‐チョークコイル３ａ，３ｂのそれぞれのインダクタンス値の特性図を図５に示した。ここで、アンテナ利得差とは、３〜２２ＭＨｚにおける、最高アンテナ利得と最低アンテナ利得との差をいう。 Antenna gain difference at 3 to 22 MHz when choke coils 3a and 3b are changed to 0.1 μH, 0.2 μH, 0.5 μH and 1.0 μH when L _x is 800 mm and choke coil 3a 3b is a characteristic diagram of the inductance values of 3b and 3b. Here, the antenna gain difference means a difference between the highest antenna gain and the lowest antenna gain at 3 to 22 MHz.

チョークコイル３ａ，３ｂのそれぞれのインダクタンス値を０．２μＨとしたときのアンテナ利得差‐Ｌ_ｘの特性図を図６に示した。第２のアンテナ導体７の、アンテナ利得‐ＦＭ放送帯の周波数の特性図を図７に示した。バスバ５ｂから給電した場合の、アンテナ利得‐ＦＭ放送帯の周波数の特性図を図８に示した。 FIG. 6 shows a characteristic diagram of the antenna gain difference −L _x when the inductance values of the choke coils 3a and 3b are 0.2 μH. A characteristic diagram of the antenna gain-FM frequency band of the second antenna conductor 7 is shown in FIG. FIG. 8 shows a characteristic diagram of the frequency of the antenna gain-FM broadcast band when power is supplied from the bus bar 5b.

Ｌ_ｘ７４５ｍｍ、
Ｌ_ｙ８０ｍｍ、
デフォガの最大縦幅ｍｍ、
デフォガの最大横幅ｍｍ、
デフォガの浮遊容量１５０ｐＦ、
第２のアンテナ導体の浮遊容量２０ｐＦ。 L _x 745mm,
L _y 80mm,
Maximum defogger width mm,
Defogger maximum width mm,
Defogger's stray capacitance 150pF,
The stray capacitance of the second antenna conductor is 20 pF.

本発明は、ＳＷ放送帯の受信に利用される。 The present invention is used for receiving the SW broadcast band.

本発明の自動車用高周波ガラスアンテナ装置の一実施例の構成図。The block diagram of one Example of the high frequency glass antenna apparatus for motor vehicles of this invention. 本発明の自動車用高周波ガラスアンテナ装置の別の実施例の構成図。The block diagram of another Example of the high frequency glass antenna apparatus for motor vehicles of this invention. 実施例における、Ｌ_ｘを８００ｍｍとして、チョークコイル３ａ，３ｂのそれぞれのインダクタンス値を０．１μＨ、０．２μＨ、０．５μＨ及び１．０μＨに変化させたときの、アンテナ利得‐周波数の特性図。In the embodiment, when L _x is 800 mm and the inductance values of the choke coils 3a and 3b are changed to 0.1 μH, 0.2 μH, 0.5 μH and 1.0 μH, the antenna gain-frequency characteristic diagram . 実施例における、チョークコイル３ａ，３ｂのそれぞれのインダクタンス値を０．２μＨとして、Ｌ_ｘを５００ｍｍ、８００ｍｍ及び１１００ｍｍに変化させたときの、アンテナ利得‐周波数の特性図。In Examples, a choke coil 3a, the respective inductance values of 3b as 0.2MyuH, when changing the _{L x} 500 mm, the 800mm and 1100 mm, antenna gain - characteristic diagram of frequency. 実施例における、Ｌ_ｘを８００ｍｍとし、チョークコイル３ａ，３ｂのそれぞれのインダクタンス値を０．１μＨ、０．２μＨ、０．５μＨ及び１．０μＨに変化させたときの、３〜２２ＭＨｚにおけるアンテナ利得差‐チョークコイル３ａ，３ｂのそれぞれのインダクタンス値の特性図。The antenna gain difference at 3 to 22 MHz when L _x is 800 mm and the inductance values of the choke coils 3 a and 3 b are changed to 0.1 μH, 0.2 μH, 0.5 μH and 1.0 μH in the embodiment. -Characteristic diagram of inductance values of choke coils 3a and 3b. 実施例における、チョークコイル３ａ，３ｂのそれぞれのインダクタンス値を０．２μＨとしたときのアンテナ利得差‐Ｌ_ｘの特性図。Characteristic diagram of the antenna gain difference -L _x upon the embodiment, a choke coil 3a, the respective inductance values of 3b and 0.2MyuH. 第２のアンテナ導体７の、アンテナ利得‐ＦＭ放送帯の周波数の特性図。The antenna gain-FM frequency band characteristic diagram of the second antenna conductor 7. バスバ５ｂから給電した場合の、アンテナ利得‐ＦＭ放送帯の周波数の特性図。The antenna gain-FM broadcast band frequency characteristic diagram when power is supplied from the bus bar 5b.

Explanation of symbols

１：自動車の後部窓ガラス板
２：ヒータ線
３ａ，３ｂ：チョークコイル
４：第１のアンテナ導体
５ａ：第１のバスバ
５ｂ：第２のバスバ
６：フィルタ回路
６ａ：コンデンサ
６ｂ：コイル
７：第２のアンテナ導体
８：前置増幅器
８ａ：同軸ケーブル
９：直流電源
１１：短絡線
Ｌ_Ｘ：第１のアンテナ導体の最大横幅
Ｌ_Ｙ：第１のアンテナ導体の最大縦幅 1: Automotive rear window glass plate 2: heater wires 3a, 3b: choke coil 4: first antenna conductor 5a: first bus bar 5b: second bus bar 6: filter circuit 6a: capacitor 6b: coil 7: first 2 antenna conductor 8: preamplifier 8a: coaxial cable 9: DC power supply 11: short circuit line L _X : maximum horizontal width L _{Y of} the first antenna conductor: maximum vertical width of the first antenna conductor

Claims

An electric heating type defogger having a large number of heater wires and a plurality of bus bars for supplying electric power to the heater wires is provided on the rear window glass plate of the automobile, and a margin part of the rear window glass plate other than the area of the defogger Is provided with an antenna conductor, a first choke coil is connected between one bus bar and a DC power source, and a second choke coil is connected between the other bus bar and ground. High frequency glass antenna device for
The antenna conductor has a function of receiving at least the SW broadcast band,
The antenna conductor and the defogger are capacitively coupled in the SW broadcast band,
A high-frequency glass antenna device for an automobile, characterized in that a resonance frequency of resonance generated mainly by an impedance of a defogger, an impedance of a first choke coil, and an impedance of a second choke coil does not exist in 3 to 22 MHz.

2. The high-frequency glass antenna device for an automobile according to claim 1, wherein the first choke coil and the second choke coil each have a function of blocking or attenuating a frequency of a SW broadcast band.

When the antenna conductor is referred to as a first antenna conductor,
A second antenna conductor is provided between the first antenna conductor and the defogger;
The high frequency glass antenna device for an automobile according to claim 1 or 2, wherein the second antenna conductor has a function of receiving at least an FM broadcast band.

The high frequency glass antenna device for an automobile according to any one of claims 1 to 3, wherein the resonance frequency exists between the SW broadcast band and the FM broadcast band.

5. The high-frequency glass antenna device for an automobile according to claim 1, wherein each of the first choke coil and the second choke coil has a function of blocking or attenuating a frequency of an FM broadcast band.

The said 1st antenna conductor is provided with the several antenna element, The area | region of the said rear window glass board which a 1st antenna conductor occupies is 0.06 m < ² > or more, The any one of Claims 2-4 High-frequency glass antenna device for automobiles.

When the inductance value of the first choke coil and the inductance value of the second choke coil are L _c and the stray capacitance of the defogger is C _d ,
(1 / (2Π)) · (L _c · C _d ) ^−0.5 is 22 to 50 MHz. The high-frequency glass antenna device for an automobile according to claim 1.

The first antenna conductor has a function of receiving an AM broadcast band;
The high frequency glass antenna device for an automobile according to any one of claims 3 to 7, wherein the first antenna conductor and the defogger are not substantially capacitively coupled in the AM broadcast band.

The high frequency glass antenna device for an automobile according to any one of claims 3 to 8, wherein an interval between the first antenna conductor and the defogger is 32 mm or more.

The high-frequency glass antenna device for an automobile according to any one of claims 3 to 9, wherein a width of the first antenna conductor is 630 to 1030 mm.

The second antenna conductor includes an element having a conductor length of 300 to 500 mm;
An interval between the first antenna conductor and the second antenna conductor is 15 to 45 mm;
The high-frequency glass antenna device for an automobile according to any one of claims 3 to 11, wherein a distance between the second antenna conductor and the defogger is 5 to 15 mm.

The automotive high-frequency glass antenna device according to claim 1, wherein the defogger has a stray capacitance of 80 to 200 pF.