JPH0983025A - Frequency converter - Google Patents
Frequency converterInfo
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- JPH0983025A JPH0983025A JP7235610A JP23561095A JPH0983025A JP H0983025 A JPH0983025 A JP H0983025A JP 7235610 A JP7235610 A JP 7235610A JP 23561095 A JP23561095 A JP 23561095A JP H0983025 A JPH0983025 A JP H0983025A
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- Prior art keywords
- frequency
- high frequency
- superconducting
- current
- josephson
- Prior art date
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、高周波発振装置、
特に駆動高周波信号（入力信号）に対して整数倍の周波
数を発生する周波数変換（逓倍）装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency oscillator,
In particular, the present invention relates to a frequency conversion (multiplication) device that generates a frequency that is an integral multiple of a driving high frequency signal (input signal).
【０００２】[0002]
【従来の技術及び発明が解決しようとする課題】現在、
衛星通信や移動体通信等において、１〜４０ＧＨｚ帯を
搬送波に用いた高周波通信システムが実用化されてい
る。この周波数帯域において、搬送波電力や参照波とし
て用いられる安定度の高い高周波信号を得るために、ガ
ンダイオードやインパットダイオード等の半導体素子に
よる直接発振、あるいは水晶振動子の出力を非線形素子
に与え、高次高調波を取り出す周波数逓倍器等が用いら
れている。2. Description of the Related Art
In satellite communication, mobile communication, etc., a high-frequency communication system using a 1-40 GHz band as a carrier has been put into practical use. In this frequency band, in order to obtain a highly stable high-frequency signal used as carrier power or reference wave, direct oscillation by a semiconductor element such as a Gunn diode or an impatt diode, or the output of a crystal oscillator is given to a nonlinear element, Frequency multipliers and the like that extract high-order harmonics are used.
【０００３】一方、その他の発振源として、ジョセフソ
ン効果を用いたものが提案されている。ジョセフソン素
子では、素子両端の電圧に応じて高周波発振が生じる交
流ジョセフソン効果や、素子に磁場を印加することによ
って生じる磁束フロー発振と呼ばれる高周波発振現象が
知られている（参考文献 例えば：ＡｎｔｏｎｉｏＢａ
ｒｏｎｅ ａｎｄ Ｇｉａｎｆｒａｎｃｏ Ｐａｔｅｒ
ｎｏ、 Ｐｈｙｓｉｃｓ ａｎｄ Ａｐｐｌｉｃａｔｉ
ｏｎｓ ｏｆ Ｔｈｅ ＪｏｓｅｐｈｓｏｎＥｆｆｅｃ
ｔ、１９８２ Ｊｈｏｎ Ｗｉｌｅｙ ＆ Ｓｏｎｓ，
Ｉｎｃ．，Ｎｅｗ Ｙｏｒｋ， Ｕ．Ｓ．Ａ．）。電
圧状態のジョセフソン素子の両端子間には、交流ジョセ
フソン効果による交流発振が存在し、その発振周波数
（ｆ）は、以下の（数１）で表される。On the other hand, as another oscillation source, one using the Josephson effect has been proposed. In the Josephson element, an AC Josephson effect in which high-frequency oscillation occurs depending on the voltage across the element and a high-frequency oscillation phenomenon called magnetic flux flow oscillation caused by applying a magnetic field to the element are known (reference document: Antonio Ba).
Rone and Gianfranco Pater
no, Physics and Applicati
ons of the Josephson Effec
t, 1982 Jhon Wiley & Sons,
Inc. , New York, U.S.A. S. A. ). AC oscillation due to the AC Josephson effect exists between both terminals of the Josephson element in the voltage state, and its oscillation frequency (f) is represented by the following (Equation 1).
【０００４】[0004]
【数１】ｆ＝２ｅＶ／ｈ## EQU1 ## f = 2 eV / h
【０００５】ここで、ｅは素電荷であり、ｈはプランク
定数、Ｖは素子の電極間の電圧である。従って、ジョセ
フソン素子は、その両端の電圧を変化させることによ
り、周波数が変化する発振素子として動作し、その周波
数の値は４８３ＧＨｚ／ｍＶである。また、その上限周
波数は、用いる超伝導体の超伝導エネルギーギャップ
（２Δ）程度までである。金属系超伝導体であるＮｂ
（２Δ〜２ｍｅＶ）を用いたジョセフソン素子では約１
ＴＨｚ、酸化物高温超伝導体であるＹ1Ｂａ2Ｃｕ3Ｏ7 -x
（但し、ｘ≦１）（２Δ〜２０ｍｅＶ）では約１０ＴＨ
ｚ程度にまで達する。Here, e is elementary charge, h is Planck's constant, and V is voltage between electrodes of the device. Therefore, the Josephson element operates as an oscillating element whose frequency changes by changing the voltage across it, and the value of the frequency is 483 GHz / mV. The upper limit frequency is up to the superconducting energy gap (2Δ) of the superconductor used. Nb, a metal-based superconductor
About 1 for a Josephson device using (2Δ to 2 meV)
THz, oxide high temperature superconductor Y 1 Ba 2 Cu 3 O 7 -x
(However, x ≦ 1) (2Δ to 20 meV) approximately 10 TH
reach about z.
【０００６】高周波通信システムにおいて、ミリ波帯、
さらにはサブミリ波帯は、将来その利用が期待される周
波数領域である。しかしながら、現在のところ、これら
の周波数領域で用いられる、周波数安定度が高く、しか
も周波数可変の発振源が実用化されておらず、その開発
が望まれていた。一般に、ミリ波（約１００ＧＨｚ）以
上の高周波の領域では、通常の半導体素子を用いた周波
数逓倍は動作しない。そのため、周波数発振装置とし
て、ガンダイオードやインパットダイオード等の半導体
素子の直接発振、あるいはジョセフソン素子の交流ジョ
セフソン効果を用いた発振等の応用が考えられる。In a high frequency communication system, a millimeter wave band,
Furthermore, the submillimeter wave band is a frequency region that is expected to be used in the future. However, at present, an oscillation source having high frequency stability and variable frequency, which is used in these frequency regions, has not been put into practical use, and its development has been desired. Generally, in a high frequency region of millimeter waves (about 100 GHz) or higher, frequency multiplication using an ordinary semiconductor element does not operate. Therefore, as a frequency oscillating device, application such as direct oscillation of a semiconductor element such as a Gunn diode or an impatt diode, or oscillation using an AC Josephson effect of a Josephson element can be considered.
【０００７】しかしながら、ガンダイオードやインパッ
トダイオード等の半導体素子を用いた周波数発振装置
は、基本的に発振周波数が固定され、周波数を広帯域で
変化させることは困難である。一方、ジョセフソン素子
を用いた周波数発振装置は、端子電圧を制御することで
広帯域の発振が可能であるが、単一の素子で得られる出
力が小さく、また周波数安定度が電圧ノイズに比例する
ため安定度が低く、さらに発振線幅が広いという問題点
を有している。However, in a frequency oscillating device using a semiconductor element such as a Gunn diode or an impat diode, the oscillation frequency is basically fixed, and it is difficult to change the frequency in a wide band. On the other hand, the frequency oscillating device using the Josephson element can oscillate in a wide band by controlling the terminal voltage, but the output obtained by a single element is small, and the frequency stability is proportional to the voltage noise. Therefore, there are problems that the stability is low and the oscillation line width is wide.
【０００８】一方、ジョセフソン素子に、外部より高周
波の電磁波を印加すると、交流ジョセフソン効果との相
互作用により、印加周波数に応じた電圧の整数倍のとこ
ろに電流ステップを生じる。これは通常シャピロステッ
プといい、良く知られた現象である。高次のシャピロス
テップ上では（電圧は一定であり、交流ジョセフソン効
果の関係式が成り立つので）印加周波数の整数倍の周波
数で発振が起こっている。外部より周波数安定度の高い
発振器の出力をジョセフソン素子に印加し、この電流ス
テップにバイアスすれば、安定な周波数逓倍器として動
作する。しかし、この電流ステップの高さは、高次にな
るほど（高周波になるほど）小さくなり、すなわち電流
バイアスが困難になる。また、高い出力の高周波発振を
得る目的で複数個のジョセフソン素子を用いる場合、多
くの素子をアレイ化することが提案されている。しか
し、これら多数のジョセフソン素子を同一条件でバイア
スし動作せることはさらに困難である。従って、各素子
のバイアス条件をなるべく緩和することが要求されてい
る。On the other hand, when a high frequency electromagnetic wave is applied to the Josephson element from the outside, a current step is generated at an integral multiple of the voltage according to the applied frequency due to the interaction with the alternating Josephson effect. This is usually known as the Shapiro step, a well-known phenomenon. On the higher order Shapiro step (since the voltage is constant and the relational expression of the AC Josephson effect holds), oscillation occurs at a frequency that is an integral multiple of the applied frequency. If the output of the oscillator with high frequency stability is applied to the Josephson element from the outside and biased to this current step, it operates as a stable frequency multiplier. However, the height of this current step becomes smaller as the order becomes higher (as the frequency becomes higher), that is, the current bias becomes difficult. Further, when a plurality of Josephson devices are used for the purpose of obtaining high-power high-frequency oscillation, it has been proposed to array many devices. However, it is more difficult to bias and operate these many Josephson devices under the same conditions. Therefore, it is required to relax the bias condition of each element as much as possible.
【０００９】本発明は上記従来の問題点を解決するため
になされたものであり、第１にミリ波帯又はサブミリ波
帯での高周波電力発振源を提供することを目的とし、第
２にジョセフソン素子用いた逓倍器におけるジョセフソ
ン素子に存在する上記特有の問題点を解決する手段を提
供することを目的としている。The present invention has been made in order to solve the above-mentioned conventional problems. The first object of the present invention is to provide a high frequency power oscillation source in the millimeter wave band or the submillimeter wave band, and secondly, Joseph. It is an object of the present invention to provide means for solving the above-mentioned peculiar problems existing in the Josephson element in the multiplier using the Son element.
【００１０】[0010]
【課題を解決するための手段】上記目的を達成するた
め、本発明の周波数変換装置は、複数のジョセフソン素
子を含む直流駆動超伝導量子干渉計（ｄｃ−ＳＱＵＩ
Ｄ）を所定数含む超伝導素子モジュールと、前記超伝導
素子モジュールの一部に磁気的に結合された電流線路と
を具備する。In order to achieve the above object, the frequency conversion device of the present invention is a direct current driven superconducting quantum interferometer (dc-SQUI) including a plurality of Josephson elements.
A superconducting element module containing a predetermined number of D) and a current line magnetically coupled to a part of the superconducting element module.
【００１１】上記構成において、前記超伝導素子モジュ
ールの一部に直流磁場を印加したことが好ましい。ま
た、上記各構成において、前記所定数のｄｃ−ＳＱＵＩ
Ｄが電気回路的に並列に接続され、前記超伝導素子モジ
ュールに単一のバイアス電源が接続されたことが好まし
い。In the above structure, it is preferable that a DC magnetic field is applied to a part of the superconducting element module. Further, in each of the above configurations, the predetermined number of dc-SQUIs
It is preferable that D is electrically connected in parallel and a single bias power source is connected to the superconducting element module.
【００１２】また、上記構成において、前記所定数のｄ
ｃ−ＳＱＵＩＤのうち、少なくとも１つに対して、電気
回路的に直列にスイッチング素子が接続されたことが好
ましい。In the above structure, the predetermined number of d
It is preferable that a switching element is connected in series to at least one of the c-SQUIDs in an electric circuit manner.
【００１３】または、上記構成において、前記所定数の
ｄｃ−ＳＱＵＩＤが電気回路的に直列に接続され、前記
超伝導素子モジュールに単一のバイアス電源が接続され
たことが好ましい。Alternatively, in the above structure, it is preferable that the predetermined number of dc-SQUIDs are connected in series in an electric circuit and a single bias power source is connected to the superconducting element module.
【００１４】また、上記各構成において、前記所定数の
ｄｃ−ＳＱＵＩＤのうち、少なくとも１つに対して、電
気回路的に並列にスイッチング素子が接続されたことが
好ましい。Further, in each of the above-mentioned structures, it is preferable that a switching element is connected in parallel in an electric circuit to at least one of the predetermined number of dc-SQUIDs.
【００１５】[0015]
【発明の実施の形態】本発明の周波数変換装置は、ジョ
セフソン素子で構成される直流駆動超伝導量子干渉計
（ｄｃ−ＳＱＵＩＤ）を所定数含むように超伝導素子モ
ジュールを形成し、その超伝導素子モジュールの一部に
駆動高周波信号用の電流線路を磁気的に結合し、その超
伝導素子モジュールの一部に直流磁場を印加するように
構成されている。所定数のｄｃ−ＳＱＵＩＤは電気回路
的に並列又は直列に接続され、各超伝導素子モジュール
に単一の直流バイアス電源が接続されている。さらに、
所定のｄｃ−ＳＱＵＩＤに対して、電気回路的に直列又
は並列にスイッチング素子が接続されている。BEST MODE FOR CARRYING OUT THE INVENTION The frequency converter of the present invention is a superconducting element module formed by including a predetermined number of direct current driven superconducting quantum interferometers (dc-SQUIDs) composed of Josephson elements. A current line for driving high frequency signals is magnetically coupled to a part of the conductive element module, and a DC magnetic field is applied to a part of the superconductive element module. A predetermined number of dc-SQUIDs are electrically connected in parallel or in series, and a single DC bias power source is connected to each superconducting element module. further,
Switching elements are connected in series or in parallel in an electric circuit to a predetermined dc-SQUID.
【００１６】Ｇ．Ｓ．Ｌｅｅらは、ｄｃ−ＳＱＵＩＤに
印加する磁場を高周波とすることにより、単独のジョセ
フソン素子に比べて高次のシャピロステップの高さが大
きくなることを見いだしている。（Ｇ．Ｓ．Ｌｅｅ、
Ｈ．Ｌ．Ｋｏ、Ｒ．Ｃ．Ｒｕｂｙ、Ａ．Ｔ．Ｂａｒｆｋ
ｎｅｃｈｔ：ＩＥＥＥ Ｔｒａｎｓ．Ａｐｐｌ．Ｓｕｐ
ｅｒ．３、２７４０−２７４３（１９９３）参照）。本
発明者らは、この現象を利用し、さらにｄｃ−ＳＱＵＩ
Ｄを所定の個数用いることにより、非常に周波数安定性
が高い高周波発振器を構成できることを見いだした。G. S. Lee et al. Found that when the magnetic field applied to the dc-SQUID has a high frequency, the height of higher-order Shapiro steps becomes larger than that of a single Josephson device. (GS Lee,
H. L. Ko, R.K. C. Ruby, A .; T. Barfk
necht: IEEE Trans. Appl. Sup
er. 3, 2740-2743 (1993)). The present inventors take advantage of this phenomenon and further use dc-SQUI
It has been found that a high frequency oscillator having extremely high frequency stability can be constructed by using a predetermined number of D.
【００１７】すなわち、ジョセフソン素子で構成される
直流駆動超伝導量子干渉計（ｄｃ−ＳＱＵＩＤ）を、所
定数含む超伝導素子モジュールを形成し、これらを電気
的に並列又は直列に結合し、さらにその超伝導素子モジ
ュールの一部に駆動高周波信号用電流線路を磁気的に結
合し、この電流線路に駆動高周波電流を流すことによ
り、駆動電流の偶数倍の高周波電力を発生させ、外部に
取り出すことができることを見いだした。さらに、超伝
導素子モジュールの一部に直流磁場を印加することによ
り、駆動電流の奇数倍の高周波電力を発生させ、外部に
取り出すことができることを見いだした。さらに、所定
のｄｃ−ＳＱＵＩＤに対して、電気回路的に直列又は並
列にスイッチング素子を接続することにより、出力電力
を調整できることを見いだした。これらの周波数変換装
置は、周波数逓倍型の動作をしており、駆動する高周波
の電流振幅（電力値）によりその逓倍次数を変化するこ
とができる。また、電流バイアス条件は、動作次数にお
いても（高次の動作状態でも）ｄｃ−ＳＱＵＩＤの臨界
電流値以下の広い範囲で有効であることを見いだした。
さらに、取り出せる高周波の周波数安定度は、駆動高周
波電流の安定度に比例しており、高い安定度の駆動電源
を用いることにより、非常に安定な出力が得られること
を見いだした。That is, a superconducting device module including a predetermined number of DC driven superconducting quantum interferometers (dc-SQUIDs) composed of Josephson devices is formed, and these are electrically connected in parallel or in series. A current line for driving high-frequency signals is magnetically coupled to a part of the superconducting element module, and a driving high-frequency current is passed through this current line to generate high-frequency power that is an even multiple of the driving current, and to take it out to the outside. I found that I can do it. Further, it was found that by applying a DC magnetic field to a part of the superconducting element module, high frequency power of an odd number times the driving current can be generated and taken out to the outside. Furthermore, they have found that the output power can be adjusted by connecting a switching element in series or in parallel in an electric circuit to a predetermined dc-SQUID. These frequency conversion devices operate in a frequency multiplication type, and their multiplication order can be changed according to the driving high frequency current amplitude (power value). It was also found that the current bias condition is effective in a wide range below the critical current value of dc-SQUID even in the operation order (even in the higher order operation state).
Furthermore, it was found that the frequency stability of the high frequency that can be taken out is proportional to the stability of the driving high frequency current, and that a very stable output can be obtained by using a driving power source with high stability.
【００１８】[0018]
【実施例１】以下、本発明の周波数変換装置の第１の実
施例を図１を参照しつつ説明する。図１は本発明の周波
数変換装置の第１の実施例の主要部分を示す電気的等価
回路図である。図１において、ジョセフソン素子１を２
個並列に接続し直流駆動超伝導量子干渉計（ｄｃ−ＳＱ
ＵＩＤ）１０ａ、１０ｂ、１０ｃ、１０ｄ・・・を形成
し、それぞれを１つの超伝導素子モジュールとする。た
だし、超伝導素子モジュールのインピーダンスの設計値
により、複数のｄｃ−ＳＱＵＩＤを並列に並べても良
い。First Embodiment A first embodiment of the frequency conversion device of the present invention will be described below with reference to FIG. FIG. 1 is an electrical equivalent circuit diagram showing a main part of a first embodiment of a frequency conversion device of the invention. In FIG. 1, the Josephson device 1 has two
Directly connected superconducting quantum interferometer (dc-SQ)
UIDs 10a, 10b, 10c, 10d, ... Are formed to form one superconducting element module. However, a plurality of dc-SQUIDs may be arranged in parallel depending on the design value of the impedance of the superconducting element module.
【００１９】図１に示す第１の実施例では、ｄｃ−ＳＱ
ＵＩＤ１０ａ・・・を直流的に並列に構成し、さらにそ
のｄｃ−ＳＱＵＩＤ１０ａ・・・を並列に電流バイアス
するように接続している。これにより、すべてのｄｃ−
ＳＱＵＩＤ１０ａ・・・の端子電圧を同一とし、従って
発振周波数を同一とすることができる。さらに、ｄｃ−
ＳＱＵＩＤ１０ａ・・・間の所定の部分をキャパシタ４
で接続し、高周波信号に対する位相を一致させる。これ
により、各ｄｃ−ＳＱＵＩＤ１０ａ・・・の高周波発振
電力を有効に加え合わせ、全体の発振電流の振幅を大き
くすることができる。また、各ｄｃ−ＳＱＵＩＤ１０ａ
・・・に平行に近接する形で、駆動高周波信号用伝送線
路３が設けられている。駆動高周波信号用伝送線路３に
高周波電力を印加することにより、駆動高周波信号用伝
送線路３とｄｃ−ＳＱＵＩＤ１０ａ・・・との間に磁気
結合６が生ずる。In the first embodiment shown in FIG. 1, dc-SQ
The UIDs 10a ... Are arranged in parallel in a direct current manner, and the dc-SQUIDs 10a are connected in parallel so as to be current biased. This allows all dc-
The terminal voltages of the SQUIDs 10a ... Can be made the same, and therefore the oscillation frequencies can be made the same. Furthermore, dc-
SQUID 10a ... The capacitor 4 is provided at a predetermined portion between
And connect them to match the phase with the high frequency signal. As a result, the high frequency oscillation power of each dc-SQUID 10a ... Can be effectively added to increase the amplitude of the entire oscillation current. Also, each dc-SQUID 10a
The driving high-frequency signal transmission line 3 is provided so as to be close to and parallel to. By applying high frequency power to the driving high frequency signal transmission line 3, a magnetic coupling 6 is generated between the driving high frequency signal transmission line 3 and the dc-SQUID 10a.
【００２０】この周波数変換装置に接続される出力用高
周波伝送線路として、例えば５０Ωに設計したマイクロ
ストリップ型又はコプレーナ型伝送線路を用いる場合、
周波数変換装置と伝送線路間のインピーダンスマッチン
グを取るために、超伝導素子モジュールを構成するジョ
セフソン素子１の数、並びに超伝導素子モジュール自体
の数を適宜選択して、周波数変換装置全体のインピーダ
ンスを５０Ωとする。超伝導素子モジュールの素子抵抗
は、並列に接続するｄｃ−ＳＱＵＩＤ１０ａ・・・の数
に比例して小さくなるが、キャパシタ４により、高周波
的に等価的に直列となるよう構成できるので、所定数の
超伝導素子モジュールを用いることにより、周波数変換
回路のインピーダンスを制御できる。これにより、外部
の、例えば５０Ω伝送線路に有効に高周波電力を取り出
すことができる。When a microstrip type or coplanar type transmission line designed to have, for example, 50Ω is used as the output high frequency transmission line connected to this frequency converter,
In order to obtain impedance matching between the frequency conversion device and the transmission line, the number of Josephson elements 1 forming the superconducting element module and the number of superconducting element modules themselves are appropriately selected to determine the impedance of the entire frequency conversion apparatus. It is set to 50Ω. The element resistance of the superconducting element module decreases in proportion to the number of dc-SQUIDs 10a ... Connected in parallel, but since it can be configured to be equivalent in series at high frequency by the capacitor 4, a predetermined number of elements can be formed. The impedance of the frequency conversion circuit can be controlled by using the superconducting element module. Thereby, the high frequency power can be effectively taken out to the outside, for example, the 50Ω transmission line.
【００２１】[0021]
【実施例２】次に、本発明の周波数変換装置の第２の実
施例を図２を参照しつつ説明する。図２は本発明の周波
数変換装置の第２の実施例の主要部分を示す電気的等価
回路図である。図２において、ジョセフソン素子１を２
個並列に接続してｄｃ−ＳＱＵＩＤ１０ａ・・・を形成
し、それぞれを１つの超伝導素子モジュールとする。１
つの超伝導素子モジュールにおけるｄｃ−ＳＱＵＩＤの
数は、超伝導素子モジュールのインピーダンス設計値に
より、複数であってもよく、必ず１つで構成しなくては
いけないというものではない。Second Embodiment Next, a second embodiment of the frequency conversion device of the present invention will be described with reference to FIG. FIG. 2 is an electrical equivalent circuit diagram showing the main part of the second embodiment of the frequency conversion device of the invention. In FIG. 2, the Josephson device 1 has two
.. are connected in parallel to form dc-SQUIDs 10a ..., Each of which constitutes one superconducting element module. 1
The number of dc-SQUIDs in one superconducting element module may be plural depending on the impedance design value of the superconducting element module, and it is not always necessary to configure one.
【００２２】図２に示す第２の実施例では、各ｄｃ−Ｓ
ＱＵＩＤ１０ａ・・・は直列に電流バイアスするように
接続されている。各ｄｃ−ＳＱＵＩＤ１０ａ・・・間の
接続は薄膜伝送線路型（実際にはマイクロストリップ
型）の伝送線路７により、高周波信号の位相を各ｄｃ−
ＳＱＵＩＤ１０ａ・・・間で一致させる又は周期的に変
化させる構造とした。In the second embodiment shown in FIG. 2, each dc-S
The QUIDs 10a ... Are connected so as to be current-biased in series. The connection between the dc-SQUIDs 10a, ...
The SQUIDs 10a ... Have a structure in which they are matched or periodically changed.
【００２３】第１の実施例と同様に、この周波数変換装
置に接続される出力用高周波伝送線路として、例えば５
０Ωに設計したマイクロストリップ型又はコプレーナ型
伝送線路を用いる場合、周波数変換装置と伝送線路間の
インピーダンスマッチングを取るために、超伝導素子モ
ジュールを構成するジョセフソン素子１の数、並びに超
伝導素子モジュール自体の数を適宜選択して、周波数変
換装置全体のインピーダンスを５０Ωとする。Similar to the first embodiment, the output high frequency transmission line connected to the frequency converter is, for example, 5
When a microstrip type or coplanar type transmission line designed to 0Ω is used, the number of Josephson elements 1 constituting the superconducting element module and the superconducting element module are used for impedance matching between the frequency conversion device and the transmission line. The impedance of the entire frequency conversion device is set to 50Ω by appropriately selecting the number of itself.
【００２４】上記第１及び第２の実施例では、各ｄｃ−
ＳＱＵＩＤ１０ａ・・・間の接続をキャパシタ４又は伝
送線路７としたが、高周波電力の位相を決定できるよう
な回路であればどのような構成でも良く、例えば抵抗成
分やインダクタンス成分を含むものでもよい。また、上
記第１及び第２の実施例では直流磁場印加用の構成には
していないが、駆動高周波信号用電流線路３に直流電流
を重畳することにより等価的にｄｃ−ＳＱＵＩＤ１０ａ
・・・に直流磁場を印加する構成としてもよい。また、
これとは別に独立に磁場印加機構を設けても良い。簡単
には、駆動高周波信号用電流線路３と同様に、ｄｃ−Ｓ
ＱＵＩＤ１０ａ・・・に近接させてもうひとつ電流線路
を設けたり、ｄｃ−ＳＱＵＩＤ１０ａ・・・に結合する
形で薄膜コイルを形成しても良い。In the first and second embodiments, each dc-
The connection between the SQUIDs 10a ... Is made to be the capacitor 4 or the transmission line 7, but any configuration may be used as long as it is a circuit capable of determining the phase of the high frequency power, for example, one including a resistance component or an inductance component. The first and second embodiments are not configured to apply a DC magnetic field, but by superposing a DC current on the drive high-frequency signal current line 3, the dc-SQUID 10a is equivalently obtained.
.. may be applied with a DC magnetic field. Also,
Separately from this, a magnetic field applying mechanism may be provided independently. Briefly, like the current line 3 for driving high frequency signal, dc-S
Another current line may be provided close to the QUIDs 10a ... Or a thin film coil may be formed by being coupled to the dc-SQUIDs 10a.
【００２５】上記第１及び第２の実施例において、ｄｃ
−ＳＱＵＩＤ１０ａ・・・に高周波スイッチング素子
（ＰＩＮダイオードなど）を付加し、適宜スイッチング
を行い、全体の高周波出力を制御できることを確認し
た。この構成は、高周波出力を適当な値に制御しなくて
はならない高周波ミキサーの局部発振源等の用途に有効
である。In the first and second embodiments described above, dc
It was confirmed that a high-frequency switching element (PIN diode or the like) was added to the SQUID 10a, and switching was appropriately performed to control the entire high-frequency output. This configuration is effective for applications such as a local oscillation source of a high frequency mixer in which the high frequency output must be controlled to an appropriate value.
【００２６】[0026]
【具体例】以下に、ジョセフソン素子を用いた周波数変
換装置の具体例を示す。基板として厚さ０．５ｍｍのＭ
ｇＯ単結晶を用い、その上にジョセフソン素子及び高周
波伝送線路を形成する構成とした。伝送線路はＡｕ薄膜
よりなるマイクロストリップ型伝送線路である。従っ
て、基板裏面全面にＡｕ薄膜を形成し、接地面を形成し
ている。超伝導素子は、いわゆる２２１２相のＢｉ系酸
化物超伝導体を用いた積相型ジョセフソン素子（参考文
献：Ｋｏｉｃｈ Ｍｉｚｕｎｏ 他 Ａｐｐｌ．Ｐｈｙ
ｓ．Ｌｅｔｔ．５６（１９９０）１４６９−１４７１；
Ｊｐｎ．Ｊ．Ａｐｐｌ．Ｐｈｙｓ．３０（１９９１）Ｌ
１５５９−Ｌ１５６１ で報告されているものと同様の
構造）であり、同一真空中で形成した多層膜より素子を
形成している。この素子構造はジョセフソン素子を並列
にアレイ化するのに適した素子構造である。Specific Example A specific example of a frequency conversion device using a Josephson element will be shown below. 0.5 mm thick M as a substrate
A gO single crystal was used, and a Josephson element and a high frequency transmission line were formed on it. The transmission line is a microstrip type transmission line made of an Au thin film. Therefore, an Au thin film is formed on the entire back surface of the substrate to form a ground plane. The superconducting device is a product phase type Josephson device using a so-called 2212 phase Bi-based oxide superconductor (reference: Koich Mizuno et al. Appl. Phy.
s. Lett. 56 (1990) 1469-1471;
Jpn. J. Appl. Phys. 30 (1991) L
1559-L1561) and a device is formed from a multilayer film formed in the same vacuum. This device structure is suitable for arraying Josephson devices in parallel.
【００２７】まず、ジョセフソン素子を含むｄｃ−ＳＱ
ＵＩＤを、超伝導薄膜を含む多層膜成膜および数回のパ
ターニングプロセスで形成し、その後Ａｕ薄膜を全面に
形成し、伝送線路パターン、駆動高周波信号用電流線路
及び各種パッド部分を形成し、周波数変換装置を完成さ
せた。さらに、完成した周波数変換装置の一端を高周波
伝送線路パターンに接続した。本具体例では、２個のジ
ョセフソン素子を並列接合して１つのｄｃ−ＳＱＵＩＤ
とし、１つのｄｃ−ＳＱＵＩＤで超伝導素子モジュール
を構成した。超伝導素子モジュールを７段つなげ、各段
間は薄膜キャパシタにより高周波的に結合した。なお、
１つのジョセフソン素子の素子抵抗は１Ω程度であり、
電極とのコンタクト抵抗を含めると１５Ω程度である。
従って、２個並列のｄｃ−ＳＱＵＩＤを高周波的に７段
直列とすることにより、ほぼ５０Ωのインピーダンスが
得られた。また、各ｄｃ−ＳＱＵＩＤに平行に近接する
形で、駆動高周波信号用の伝送線路を形成し、ここに流
れる高周波電力とｄｃ−ＳＱＵＩＤが磁気結合するよう
設計した。なお、ｄｃ−ＳＱＵＩＤ自体の直流駆動電源
は外部回路とし、ｄｃ−ＳＱＵＩＤに接続した。First, dc-SQ including Josephson element
The UID is formed by forming a multi-layer film including a superconducting thin film and patterning several times, then forming an Au thin film on the entire surface, forming a transmission line pattern, a current line for driving high frequency signals, and various pad portions. The converter was completed. Further, one end of the completed frequency conversion device was connected to the high frequency transmission line pattern. In this example, two Josephson devices are connected in parallel to form one dc-SQUID.
Then, the superconducting element module was configured with one dc-SQUID. Seven stages of superconducting element modules were connected, and each stage was connected at high frequency by a thin film capacitor. In addition,
The element resistance of one Josephson element is about 1Ω,
When including the contact resistance with the electrode, it is about 15Ω.
Therefore, an impedance of approximately 50Ω was obtained by connecting two parallel dc-SQUIDs in series at 7 stages in terms of high frequency. Further, a transmission line for a driving high frequency signal was formed in the form of being in parallel and close to each dc-SQUID, and the high frequency power flowing there was designed to be magnetically coupled to the dc-SQUID. The DC drive power source for the dc-SQUID itself was an external circuit and was connected to the dc-SQUID.
【００２８】この素子を５０Ｋ以下の温度に冷却したと
ころ、ｄｃ−ＳＱＵＩＤは磁束計として動作し、さらに
駆動高周波信号用電流線路に高周波電力を供給すること
により、その偶数倍の周波数の電力がｄｃ−ＳＱＵＩＤ
端子に発生することを確認した。さらに、駆動高周波信
号用電流線路に直流バイアス電流を重畳することによ
り、各ｄｃ−ＳＱＵＩＤに直流磁場を印加すると、ある
直流バイアス磁場の大きさの時に、駆動高周波信号用電
流線路に供給される高周波電力の奇数倍の周波数の出力
が得られることを確認した。When this element is cooled to a temperature of 50 K or less, the dc-SQUID operates as a flux meter, and by supplying high frequency power to the drive high frequency signal current line, power of an even multiple of that frequency is dc. -SQUID
It was confirmed that it occurred in the terminal. Furthermore, when a DC magnetic field is applied to each dc-SQUID by superimposing a DC bias current on the drive high-frequency signal current line, the high-frequency signal supplied to the drive high-frequency signal current line at a certain DC bias magnetic field magnitude. It was confirmed that an output with a frequency that was an odd multiple of the power was obtained.
【００２９】なお、他の具体例として、ｄｃ−ＳＱＵＩ
Ｄをいわゆる１２３構造のＹ系酸化物超伝導体を用いた
ステップエッジ型ジョセフソン素子（参考文献：Ｙｏｓ
ｈｉｔｏ Ｆｕｋｕｍｏｔｏ 他 Ｊｐｎ．Ｊ．Ａｐｐ
ｌ．Ｐｈｙｓ．３０（１９９１）３９０７−３９１０
で報告されているものと同様の構造）で形成した。この
場合も同様に周波数変換装置が形成できることを確認し
た。このタイプのジョセフソン素子は、基板表面に加工
した段差を利用して素子を形成しているが、基板加工、
超伝導薄膜成膜及びパターニングの３つの主要行程によ
り形成でき、製造工程が簡単であるという利点を有す
る。As another specific example, dc-SQUI
Step-edge type Josephson device using a so-called 123-structure Y-based oxide superconductor for D (reference: Yos
hito Fukumoto et al. Jpn. J. App
l. Phys. 30 (1991) 3907-3910.
The structure was similar to that reported in (1). Also in this case, it was confirmed that the frequency converter can be formed in the same manner. This type of Josephson device uses the steps processed on the substrate surface to form the device.
It can be formed by three main steps of superconducting thin film formation and patterning, and has an advantage that the manufacturing process is simple.
【００３０】さらに、本発明の周波数変換装置はジョセ
フソン効果を利用しており、用いられる超伝導体は金属
系材料（例えばＮｂ、Ｎｂ合金、ＰｂあるいはＰｂ合金
等）でも良く、また他の高温酸化物超伝導体（Ｙ系、Ｔ
ｌ系、Ｈｇ系等）でも良い。高周波伝送線路を形成する
のは、他の金属材料（Ｐｔ、Ｃｕ、Ａｇ及びこれらの合
金、Ａｕを含む合金等）でも良く、上記の超伝導体でも
良い。実際には、使用される周波数領域で最小の表面抵
抗を示す材料を用いる設計が望ましい。さらに、基板材
料は高周波での誘電損失が小さいものが望ましく、サフ
ァイア等種々の誘電材料を用いることができる。酸化物
超伝導体を用いる場合、良好な超伝導特性を得るため
に、基板材料の格子定数は超伝導体の格子定数と近いこ
とが望ましく、その点でＬａＡｌＯ3、ＬａＧａＯ3、Ｌ
ａＳｒＯ3等のペロブスカイト系単結晶も用いることが
できる。Further, the frequency converter of the present invention utilizes the Josephson effect, and the superconductor used may be a metallic material (for example, Nb, Nb alloy, Pb or Pb alloy, etc.) and other high temperature. Oxide superconductor (Y series, T
1-based, Hg-based, etc.). Other metal materials (Pt, Cu, Ag and alloys thereof, alloys containing Au, etc.) may be used to form the high frequency transmission line, or the above-mentioned superconductor may be used. In practice, it is desirable to design with a material that has a minimum surface resistance in the frequency range used. Further, it is desirable that the substrate material has a small dielectric loss at high frequencies, and various dielectric materials such as sapphire can be used. When an oxide superconductor is used, it is desirable that the lattice constant of the substrate material be close to the lattice constant of the superconductor in order to obtain good superconducting properties. In that respect, LaAlO 3 , LaGaO 3 , L
A perovskite single crystal such as aSrO 3 can also be used.
【００３１】[0031]
【発明の効果】以上述べたように、本発明の周波数変換
装置によれば、複数のジョセフソン素子を含む直流駆動
超伝導量子干渉計（ｄｃ−ＳＱＵＩＤ）を所定数含む超
伝導素子モジュールと、前記超伝導素子モジュールの一
部に磁気的に結合された電流線路とを具備するので、こ
の電流線路に駆動高周波電流を流すことにより、駆動電
流の偶数倍の高周波電力を発生させ、外部に取り出すこ
とができる。As described above, according to the frequency conversion device of the present invention, a superconducting element module including a predetermined number of DC driven superconducting quantum interferometers (dc-SQUIDs) including a plurality of Josephson elements, Since a current line magnetically coupled to a part of the superconducting element module is provided, a high-frequency electric current of even multiples of the drive current is generated by flowing a high-frequency driving current through this current line, and is taken out to the outside. be able to.
【００３２】また、超伝導素子モジュールの一部に直流
磁場を印加することにより、駆動電流の奇数倍の高周波
電力を発生させ、外部に取り出すことができる。また、
所定数のｄｃ−ＳＱＵＩＤを電気回路的に並列又は直列
に接続し、超伝導素子モジュールに単一のバイアス電源
を接続することにより、駆動する高周波の電流振幅（電
力値）によりその逓倍次数を変化することができる。ま
た、電流バイアス条件は、動作次数においても（高次の
動作状態でも）ｄｃ−ＳＱＵＩＤの臨界電流値以下の広
い範囲で有効であり、取り出せる高周波の周波数安定度
は、駆動高周波電流の安定度に比例し、高い安定度の駆
動電源を用いることにより、非常に安定な出力が得られ
る。また、所定数のｄｃ−ＳＱＵＩＤのうち、少なくと
も１つに対して、電気回路的に直列又は並列にスイッチ
ング素子を接続することにより、出力電力を調整でき
る。Further, by applying a DC magnetic field to a part of the superconducting element module, it is possible to generate a high frequency power of an odd multiple of the driving current and take it out to the outside. Also,
By connecting a predetermined number of dc-SQUIDs in parallel or series in an electric circuit and connecting a single bias power source to the superconducting element module, the multiplication order is changed according to the driving high frequency current amplitude (power value). can do. Further, the current bias condition is effective in a wide range below the critical current value of the dc-SQUID even in the operation order (even in the higher order operation state), and the frequency stability of the high frequency that can be taken out is the stability of the driving high frequency current. By using a proportional and highly stable driving power supply, a very stable output can be obtained. Moreover, the output power can be adjusted by connecting a switching element in series or in parallel in an electric circuit to at least one of the predetermined number of dc-SQUIDs.
【００３３】以上の結果、本発明の周波数変換装置は、
現在利用されあるいは将来利用が期待される数十ＧＨｚ
以上ＴＨｚに及ぶ高周波数帯域での高周波通信の局部発
振器として利用することができる。また、駆動高周波信
号として安定度の高い水晶振動子や他の発振回路の出力
を用いることにより、その逓倍の高周波電力を得ること
ができ、しかも非常に高周波まで（高次まで）動作する
ことができる。さらに、駆動電力の周波数や出力を可変
とすることにより、広帯域に出力の周波数を変化させる
ことができる。As a result of the above, the frequency conversion device of the present invention is
Dozens of GHz currently used or expected to be used in the future
It can be used as a local oscillator for high frequency communication in a high frequency band extending to THz. Also, by using a highly stable crystal oscillator or the output of another oscillation circuit as a driving high frequency signal, it is possible to obtain a high frequency power that is a multiplication thereof, and it is possible to operate up to a very high frequency (up to high order). it can. Further, by varying the frequency of the drive power and the output, the output frequency can be changed in a wide band.
【図１】本発明の周波数変換装置の第１の実施例におけ
る電気的等価回路図FIG. 1 is an electrical equivalent circuit diagram of a frequency converter according to a first embodiment of the present invention.
【図２】本発明の周波数変換装置の第２の実施例におけ
る電気的等価回路図FIG. 2 is an electrical equivalent circuit diagram in a second embodiment of the frequency conversion device of the invention.
１ ：ジョセフソン素子 ２ ：直流バイアス線 ３ ：駆動高周波信号用電流線路 ４ ：キャパシタ ５ ：直流バイアス電源 ６ ：磁気結合 １０ａ〜１０ｄ：ｄｃ−ＳＱＵＩＤ 1: Josephson element 2: DC bias line 3: Current line for driving high frequency signal 4: Capacitor 5: DC bias power supply 6: Magnetic coupling 10a to 10d: dc-SQUID
Claims (6)
超伝導量子干渉計（ｄｃ−ＳＱＵＩＤ）を所定数含む超
伝導素子モジュールと、前記超伝導素子モジュールの一
部に磁気的に結合された電流線路とを具備する周波数変
換装置。1. A superconducting device module including a predetermined number of direct current driven superconducting quantum interferometers (dc-SQUIDs) including a plurality of Josephson devices, and a current magnetically coupled to a part of the superconducting device module. A frequency conversion device comprising a line.
磁場を印加した請求項１記載の周波数変換装置。2. The frequency conversion device according to claim 1, wherein a DC magnetic field is applied to a part of the superconducting element module.
路的に並列に接続され、前記超伝導素子モジュールに単
一のバイアス電源が接続された請求項１又は２記載の周
波数変換装置。3. The frequency conversion device according to claim 1, wherein the predetermined number of dc-SQUIDs are connected in parallel in an electric circuit, and a single bias power source is connected to the superconducting element module.
少なくとも１つに対して、電気回路的に直列にスイッチ
ング素子が接続された請求項３記載の周波数変換装置。4. Of the predetermined number of dc-SQUIDs,
The frequency conversion device according to claim 3, wherein a switching element is electrically connected in series to at least one of them.
路的に直列に接続され、前記超伝導素子モジュールに単
一のバイアス電源が接続された請求項１又は２記載の周
波数変換装置。5. The frequency conversion device according to claim 1, wherein the predetermined number of dc-SQUIDs are connected in series in an electric circuit and a single bias power source is connected to the superconducting element module.
少なくとも１つに対して、電気回路的に並列にスイッチ
ング素子が接続された請求項５記載の周波数変換装置。6. Of the predetermined number of dc-SQUIDs,
The frequency conversion device according to claim 5, wherein a switching element is electrically connected in parallel to at least one of them.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23561095A JP3215021B2 (en) | 1995-09-13 | 1995-09-13 | Frequency converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23561095A JP3215021B2 (en) | 1995-09-13 | 1995-09-13 | Frequency converter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0983025A true JPH0983025A (en) | 1997-03-28 |
| JP3215021B2 JP3215021B2 (en) | 2001-10-02 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23561095A Expired - Fee Related JP3215021B2 (en) | 1995-09-13 | 1995-09-13 | Frequency converter |
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| Country | Link |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2018524795A (en) * | 2015-09-30 | 2018-08-30 | グーグル エルエルシー | Magnetic flux qubits in coplanar waveguides. |
| JP2020174199A (en) * | 2020-07-01 | 2020-10-22 | グーグル エルエルシー | Flux qubit of coplanar waveguide |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100998177B1 (en) * | 2010-06-04 | 2010-12-07 | 이병기 | Apparatus for generating electromagnetic field of high frequency capable of adjusting a magnetic field intensity and frequency and apparatus for purification of water comprising the same |
| US11362656B1 (en) | 2021-10-28 | 2022-06-14 | International Business Machines Corporation | Josephson RF to RF frequency converter |
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1995
- 1995-09-13 JP JP23561095A patent/JP3215021B2/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2018524795A (en) * | 2015-09-30 | 2018-08-30 | グーグル エルエルシー | Magnetic flux qubits in coplanar waveguides. |
| US10650320B2 (en) | 2015-09-30 | 2020-05-12 | Google Llc | Co-planar waveguide flux qubits |
| US10949769B2 (en) | 2015-09-30 | 2021-03-16 | Google Llc | Co-planar waveguide flux qubits |
| JP2020174199A (en) * | 2020-07-01 | 2020-10-22 | グーグル エルエルシー | Flux qubit of coplanar waveguide |
| JP2022111146A (en) * | 2020-07-01 | 2022-07-29 | グーグル エルエルシー | Flux qubit of coplanar waveguide |
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| Publication number | Publication date |
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| JP3215021B2 (en) | 2001-10-02 |
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