JPH06112720A - Radio receiver - Google Patents
Radio receiverInfo
- Publication number
- JPH06112720A JPH06112720A JP28532392A JP28532392A JPH06112720A JP H06112720 A JPH06112720 A JP H06112720A JP 28532392 A JP28532392 A JP 28532392A JP 28532392 A JP28532392 A JP 28532392A JP H06112720 A JPH06112720 A JP H06112720A
- Authority
- JP
- Japan
- Prior art keywords
- resistance
- circuit
- antenna
- aeff
- loop antenna
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)
- Support Of Aerials (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】この発明は、ル−プアンテナを備
える無線受信機に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio receiver having a loop antenna.
【0002】[0002]
【従来の技術】従来、小型のル−プアンテナを備える無
線受信機においては、図2の(a)に示すように、ル−
プアンテナ1の端子1a、1bには、それぞれキャパシ
タンスC1,C2が接続され、また上記端子1bにはマ
ッチング用のキャパシタンスC3を介して高周波増幅ト
ランジスタQ1のベ−スが接続している。同図の(b)
は、ル−プアンテナ1を等価直列抵抗Ra及び等価直列
インダクタンスLaで置き換えた場合の等価回路であ
る。即ち、到来電波の磁界成分は、ル−プアンテナ1に
よりアンテナ電流に変換され、このアンテナ電流は、キ
ャパシタンスC1、C3からなるインピ−ダンス整合回
路を介して高周波増幅トランジスタQ1に供給される。2. Description of the Related Art Conventionally, in a radio receiver provided with a small loop antenna, as shown in FIG.
The capacitances C1 and C2 are connected to the terminals 1a and 1b of the antenna 1, respectively, and the base of the high frequency amplification transistor Q1 is connected to the terminal 1b through a matching capacitance C3. (B) of the same figure
Is an equivalent circuit when the loop antenna 1 is replaced with an equivalent series resistance Ra and an equivalent series inductance La. That is, the magnetic field component of the incoming radio wave is converted into an antenna current by the loop antenna 1, and this antenna current is supplied to the high frequency amplification transistor Q1 via the impedance matching circuit composed of the capacitances C1 and C3.
【0003】[0003]
【発明が解決しようとする課題】ところで、ル−プアン
テナ1の上記等価直列抵抗Raは、次式に示すように2
つの成分に分けられる。 Ra=Rr+Ro ただし、Rrは放射抵抗即ちル−プアンテナ1を送信用
として用いたときの等価負荷抵抗であり、Roはオ−ミ
ック抵抗即ち損失抵抗である。そして、アンテナ効率A
effは等価直列抵抗Raがアンテナ系の全抵抗と見做
せるので次式で表わされる。 Aeff=Rr/Ra ここで、等価直列抵抗Ra即ち(Rr+Ro)は、28
0MHz帯では約1オ−ムになり、その内の大部分は損
失抵抗Roで占められており、放射抵抗Rrは、損失抵
抗Roのおよそ1/10程度になる。そのため、アンテ
ナ効率Aeffは、10パ−セント以下と極めて低いも
のになる。By the way, the equivalent series resistance Ra of the loop antenna 1 is 2 as shown in the following equation.
It is divided into two components. Ra = Rr + Ro where Rr is a radiation resistance, that is, an equivalent load resistance when the loop antenna 1 is used for transmission, and Ro is an ohmic resistance, that is, a loss resistance. And the antenna efficiency A
eff is expressed by the following equation since the equivalent series resistance Ra can be regarded as the total resistance of the antenna system. Aeff = Rr / Ra Here, the equivalent series resistance Ra, that is, (Rr + Ro) is 28
It becomes about 1 ohm in the 0 MHz band, and most of it is occupied by the loss resistance Ro, and the radiation resistance Rr becomes about 1/10 of the loss resistance Ro. Therefore, the antenna efficiency Aeff is extremely low at 10 percent or less.
【0004】本発明は上述の事情に鑑みてなされたもの
であり、アンテナ効率の高い無線受信機の提供を目的と
する。The present invention has been made in view of the above circumstances, and an object thereof is to provide a radio receiver having high antenna efficiency.
【0005】[0005]
【課題を解決するための手段】本発明は、上記目的を達
成するために、ル−プアンテナの損失抵抗の一部を相殺
する負性抵抗回路を設けた。In order to achieve the above object, the present invention provides a negative resistance circuit for canceling a part of the loss resistance of the loop antenna.
【0006】[0006]
【実施例】以下、図面に示す実施例に基づき本発明を具
体的に説明する。図1の(a)は本実施例のアンテナ系
の構成を示す回路図であり、同図の(b)はル−プアン
テナ1を等価直列抵抗Raと等価直列インダクタンスL
aとで置き換えた等価回路図である(なお、図1におい
ては、上記図2における回路部品と同一の回路部品には
同一の符号を付している)。上記図1から分かるよう
に、本実施例では、従来例におけるル−プアンテナ1の
端子1aに負性抵抗回路2を接続したものになってい
る。そして、負性抵抗回路2としては、同図(c)に示
すようなコルビッツ発振回路型回路が用いられ、同図
(b)に示すように、その負性抵抗値を(−R)として
いる(なお、同図(c)において、抵抗Rjは、負性抵
抗値の調整に用いる抵抗である)。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the embodiments shown in the drawings. FIG. 1A is a circuit diagram showing the configuration of the antenna system of the present embodiment, and FIG. 1B is a circuit diagram showing the loop antenna 1 with an equivalent series resistance Ra and an equivalent series inductance L.
2 is an equivalent circuit diagram replaced with a (in FIG. 1, the same circuit components as those in FIG. 2 are designated by the same reference numerals). As can be seen from FIG. 1 described above, in the present embodiment, the negative resistance circuit 2 is connected to the terminal 1a of the loop antenna 1 in the conventional example. Then, as the negative resistance circuit 2, a Kolwitz oscillation circuit type circuit as shown in FIG. 7C is used, and the negative resistance value is (-R) as shown in FIG. (In addition, the resistance Rj is a resistance used for adjustment of a negative resistance value in the same figure (c)).
【0007】以上の如くに構成された本実施例では、ア
ンテナ系の抵抗Rtは次式で示されるように、従来例に
おけるものすなわち等価直列抵抗Raよりも小さくなっ
ている。 Rt=Ra−kR ここで、kは、抵抗値(−R)の負性抵抗回路2とキャ
パシタンスC1との並列回路を直列回路に変換した場合
の抵抗変換係数である。そして、この場合のアンテナ効
率Aeffは以下のようになる。 Aeff=Rr/Rt=Rr/(Ra−kR) 即ち、従来例におけるアンテナ効率Aeffは前述のよ
うにRr/Raで表わされ、本実施例におけるものは、
上記の式のように、Rr/(Ra−kR)で、分母がk
Rだけ小さくなっており、それだけアンテナ係数Aef
fは大きなものになる。なお、この場合、アンテナ系の
回路抵抗の過剰低下により回路が不安定化し発振するの
を防ぐべく、上記(Ra−kR)を等価直列抵抗Raの
70〜90%(前述のように280MHzでは等価直列
抵抗Raが約1オ−ムであるから、この周波数で用いる
ときは0、7〜0、9オ−ム)にとどめるのが好まし
い。In this embodiment constructed as described above, the resistance Rt of the antenna system is smaller than that in the conventional example, that is, the equivalent series resistance Ra, as shown by the following equation. Rt = Ra-kR Here, k is a resistance conversion coefficient when a parallel circuit of the negative resistance circuit 2 having a resistance value (-R) and the capacitance C1 is converted into a series circuit. Then, the antenna efficiency Aeff in this case is as follows. Aeff = Rr / Rt = Rr / (Ra-kR) That is, the antenna efficiency Aeff in the conventional example is represented by Rr / Ra as described above, and in the present example,
As in the above formula, in Rr / (Ra-kR), the denominator is k
It is smaller by R, and the antenna coefficient Aef is correspondingly smaller.
f will be large. In this case, in order to prevent the circuit from becoming unstable and oscillating due to the excessive decrease of the circuit resistance of the antenna system, the above (Ra-kR) is equivalent to 70 to 90% of the equivalent series resistance Ra (as described above, at 280 MHz, equivalent). Since the series resistance Ra is about 1 ohm, it is preferable to limit it to 0, 7-0, 9 ohms) when used at this frequency.
【0008】また、本実施例の場合、負性抵抗回路2の
働きにより、アンテナ系のQが向上するので受信フィル
タ特性が向上し、妨害波除去能力も向上する。Further, in the case of the present embodiment, the Q of the antenna system is improved by the function of the negative resistance circuit 2, so that the receiving filter characteristic is improved and the interference wave removing capability is also improved.
【発明の効果】以上詳述したように、この発明は、ル−
プアンテナの損失抵抗の一部を相殺する負性抵抗回路を
設けた無線受信機にかかるものだから、アンテナ効率の
高い無線受信機の提供を可能とする。As described above in detail, the present invention is
Since the present invention relates to a radio receiver provided with a negative resistance circuit that cancels a part of the loss resistance of the antenna, it is possible to provide a radio receiver with high antenna efficiency.
【図1】本発明の一実施例の構成を示す回路図。FIG. 1 is a circuit diagram showing a configuration of an embodiment of the present invention.
【図2】従来例を示す図。FIG. 2 is a diagram showing a conventional example.
1 ル−プアンテナ 1a 端子 1b 端子 2 負性抵抗回路 C1 キャパシタンス C2 キャパシタンス C3 キャパシタンス Q1 高周波増幅トランジスタ La 等価直列インダクタンス Ra 等価直列抵抗 Ro 損失抵抗 Rr 放射抵抗 1 loop antenna 1a terminal 1b terminal 2 negative resistance circuit C1 capacitance C2 capacitance C3 capacitance Q1 high frequency amplification transistor La equivalent series inductance Ra equivalent series resistance Ro loss resistance Rr radiation resistance
Claims (1)
いて、 上記ル−プアンテナの損失抵抗の一部を相殺する負性抵
抗回路を備えたことを特徴とする無線受信機。1. A radio receiver having a loop antenna, comprising a negative resistance circuit for canceling a part of loss resistance of the loop antenna.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP28532392A JPH06112720A (en) | 1992-09-30 | 1992-09-30 | Radio receiver |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP28532392A JPH06112720A (en) | 1992-09-30 | 1992-09-30 | Radio receiver |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH06112720A true JPH06112720A (en) | 1994-04-22 |
Family
ID=17690059
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP28532392A Pending JPH06112720A (en) | 1992-09-30 | 1992-09-30 | Radio receiver |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH06112720A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20090284082A1 (en) * | 2008-05-13 | 2009-11-19 | Qualcomm Incorporated | Method and apparatus with negative resistance in wireless power transfers |
US8854224B2 (en) | 2009-02-10 | 2014-10-07 | Qualcomm Incorporated | Conveying device information relating to wireless charging |
-
1992
- 1992-09-30 JP JP28532392A patent/JPH06112720A/en active Pending
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20090284082A1 (en) * | 2008-05-13 | 2009-11-19 | Qualcomm Incorporated | Method and apparatus with negative resistance in wireless power transfers |
CN102027683A (en) * | 2008-05-13 | 2011-04-20 | 高通股份有限公司 | Method and apparatus with negative resistance in wireless power transfers |
JP2011524156A (en) * | 2008-05-13 | 2011-08-25 | クゥアルコム・インコーポレイテッド | Method and apparatus using negative resistance in wireless power transfer |
JP2014090429A (en) * | 2008-05-13 | 2014-05-15 | Qualcomm Incorporated | Method and apparatus with negative resistance in wireless power transfers |
US9190875B2 (en) * | 2008-05-13 | 2015-11-17 | Qualcomm Incorporated | Method and apparatus with negative resistance in wireless power transfers |
US9954399B2 (en) | 2008-05-13 | 2018-04-24 | Qualcomm Incorporated | Reverse link signaling via receive antenna impedance modulation |
US9991747B2 (en) | 2008-05-13 | 2018-06-05 | Qualcomm Incorporated | Signaling charging in wireless power environment |
US8854224B2 (en) | 2009-02-10 | 2014-10-07 | Qualcomm Incorporated | Conveying device information relating to wireless charging |
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