JP3928531B2 - Dielectric resonator, filter, duplexer, and high-frequency circuit device - Google Patents

Description

【００２１】
の関係が成り立つようにｒ１を求める。
また、
【００２２】
【数２】

【００２３】
の関係が成り立つようにｒ３を求める。
このとき理論上導体損失は最小となり、Ｑは最大となる。
【００２４】
次に、図１・図２に示した誘電体共振器の特性をシミュレーションした結果を示す。図３は上記誘電体共振器のシミュレーション用のモデルの断面図である。ここで誘電体ユニット１の上下面のうち一方の電極を薄膜多層電極２とし、他方の電極を完全導体電極３′としている。このようなモデルで各部の寸法を次のように定めた。
【００２５】
導体薄膜２１の厚み ８．２５μｍ
導体薄膜２３の厚み １μｍ
誘電体薄膜２２の厚み ０．７５μｍ
誘電体薄膜２２の誘電率 誘電体ユニットの誘電率の０．０１倍の値（比誘電率１４００））
誘電体ユニット１の厚み（導体薄膜２３と完全導体電極３′との間の距離） ０．２ｍｍ
誘電体ユニット１の直径 ０．５ｍｍ
誘電体ユニット１の比誘電率 １４００００
誘電体ユニット１の誘電体損 ０（無損失）
導体薄膜２２，２３の導電率 ５３ＭＳ
なお、誘電体ユニット１の側面は磁気壁とした。
【００２６】
図４の（Ｂ）はその結果を示している。ここで、横軸は上層の導体薄膜２１に対する下層の導体薄膜２３の径方向の長さ比、縦軸は単層電極に比べてのＱの向上比を示している。このように上層の導体薄膜に対する下層の導体薄膜の径方向寸法比を０．５５付近（面積比で０．５付近）にしたときＱは最も向上する。図中の「理論値」は、上述の〔数１〕および〔数２〕を満足するときの、上層電極に対する下層電極の径方向の長さ比である。
【００２７】
次に、第２の実施形態に係る誘電体共振器の構成を断面図として図６に示す。この例では、下層の導体薄膜２３，３３で挟まれる部分の誘電体部分１２と、それ以外の誘電体部分１１とで比誘電率を異ならせている。このような構造であっても、各導体薄膜に流入する変位電流が略等量となるように各導体薄膜の面積を定めれば、全体として最適な低損失動作が可能となる。
【００２８】
なお、第１・第２の実施形態では、２層の導体薄膜とその間に設けた１層の誘電体薄膜とによって３層構造の薄膜多層電極を設けたが、３層以上の導体薄膜を設けたものにも当然に適用できる。例えば、３層の導体薄膜と２層の誘電体薄膜とを交互に積層した５層構造の薄膜多層電極を構成する場合でも、各導体薄膜に流入する変位電流が略等量となるように、各導体薄膜の面積を上層から下層にかけて順に小さくすればよい。
【００２９】
また、第１・第２の実施形態では、円柱形状の誘電体ユニットを用いたが、誘電体ユニットの形状は円柱形状に限らず、四角柱（直方体）形状や多角柱形状であってもよい。
【００３０】
次に、第３の実施形態に係るフィルタの構成を図７を基に説明する。
図７において３つの共振器は、第１・第２の実施形態で示したいずれかの共振器であり、これらの共振器間を、図中のコンデンサの記号で表した結合容量で結合させ、さらに、初段および終段の共振器と入出力端子との間を結合容量で結合させることにより、３段の共振器からなる帯域通過フィルタ特性を有するフィルタを構成する。
【００３１】
次に、第４の実施形態としてデュプレクサの構成例を図８を参照して説明する。
ここで、送信フィルタと受信フィルタは、いずれも、図７等に示した構造のフィルタである。但し、送信フィルタは送信帯域を通過させ、受信フィルタは受信帯域を通過させるように、それぞれのフィルタ特性を定めておく。
【００３２】
送信フィルタの出力ポートと受信フィルタの入力ポートとの間は、送信信号が受信フィルタ側へ回り込まないように、また、受信信号が送信フィルタ側へ回り込まないように、位相調整を行っている。
【００３３】
次に、第５の実施形態に係る通信装置の構成を図９に示す。
ここで、デュプレクサは、図８に示した構成のデュプレクサである。このデュプレクサの送信端子には送信回路を、受信端子には受信回路をそれぞれ接続している。また、アンテナ端子にはアンテナを接続している。
【００３４】
【発明の効果】
この発明によれば、導体薄膜と誘電体薄膜とを交互に積層した薄膜多層電極のうち導体薄膜の各層に略等量の電流が流れるため、電流集中が緩和され全体の導体損失を効果的に抑制することができる。しかも、導体薄膜の面積（寸法と形成位置）によって導体損失を最も効果的に抑えるようにしたので、薄膜多層電極の誘電体薄膜部分の設計条件が広がる。
【００３５】
また、この発明によれば、上記共振器に信号入出力部を設けてフィルタを構成することにより、小型で低挿入損失なフィルタが得られる。
【００３６】
また、この発明によれば、上記フィルタを２組備えるとともに、その信号入出力部として、送信信号入力端子、共用入出力端子、および受信信号出力端子を設けてデュプレクサを構成することにより、小型で低挿入損失なデュプレクサが得られる。
【００３７】
この発明によれば、上記誘電体共振器、フィルタ、またはデュプレクサを備えて高周波回路装置を構成することにより、小型で低損失な高周波回路が構成でき、それを用いた通信装置の雑音特性および伝送速度などの通信品質を向上させることができる。
【００３８】
【図面の簡単な説明】
【図１】第１の実施形態に係る誘電体共振器の構成を示す図
【図２】同誘電体共振器の断面図
【図３】同誘電体共振器の特性シミュレーション用モデルの断面図
【図４】同誘電体共振器の誘電体薄膜の誘電率を変化させたときのＱ変化の例、および各層の導体薄膜の面積を変化させた時のＱ変化の例を示す図
【図５】ＴＭ０１０モードの電束分布と導体薄膜の形成位置との関係を示す図
【図６】第２の実施形態に係る誘電体共振器の断面図
【図７】第３の実施形態に係るフィルタの構成を示す等価回路図
【図８】第４の実施形態に係るデュプレクサの構成を示すブロック図
【図９】第５の実施形態に係る通信装置の構成を示すブロック図
【図１０】従来の誘電体共振器の構成を示す断面図
【符号の説明】
１−誘電体ユニット
２，３−薄膜多層電極
３′−完全導体電極
１１，１２−誘電体
２１，２３，３１，３３−導体薄膜
２２，３２−誘電体薄膜[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a dielectric resonator, a filter, a duplexer, and a high-frequency circuit device in, for example, a microwave band and a millimeter wave band, which are used for wireless communication and electromagnetic wave transmission / reception.
[0002]
[Prior art]
Conventionally, Patent Document 1 discloses a dielectric resonator in which a thin film multilayer electrode is formed.
This thin film multilayer electrode is formed by alternately laminating a conductor thin film and a dielectric thin film, and acts as a low-loss electrode at a high frequency. In the design method disclosed in Patent Document 1, there are optimum values of the film thickness determined according to the conductivity and the dielectric constant for the film thickness of the conductor thin film and the film thickness of the dielectric thin film. By optimizing the thickness of each of the conductor thin film and dielectric thin film, the current is distributed in a balanced manner to the layers of each conductor thin film, so the skin effect is mitigated and compared with the case of using a single layer electrode. Operates with low loss.
[0003]
In Japanese Patent Application No. 2002-238451, an application is filed for a resonator or the like in which the total conductor loss is reduced by determining the configuration of the thin film multilayer electrode formed on each surface of the dielectric unit according to the resonance mode.
[0004]
Here, FIG. 10 shows a cross-sectional view of a configuration example of a dielectric resonator including a conventional thin film multilayer electrode. In FIG. 10, 23 and 33 are the lowermost conductive thin films, 21 and 31 are the uppermost conductive thin films, and 22 and 32 are dielectric thin films provided between the conductive thin films 23, 33 and 21, 31 respectively. Thus, one thin film multilayer electrode 2 is constituted by the conductor thin film 23, the dielectric thin film 22, and the conductor thin film 21, and the other thin film multilayer electrode 3 is constituted by the conductor thin film 33, the dielectric thin film 32, and the conductor thin film 31. .
[0005]
[Patent Document 1]
International Publication No. 95/06336 Pamphlet [0006]
[Problems to be solved by the invention]
However, in a dielectric resonator in which thin film multilayer electrodes are provided on the upper and lower surfaces of a dielectric unit with open side surfaces, as shown in Patent Document 1 and the prior art of Japanese Patent Application No. 2002-238451, conductor loss The design conditions for the dielectric constant and film thickness of the dielectric thin film for reducing the above are in a narrow range.
An object of the present invention is to provide a dielectric resonator in which thin film multilayer electrodes are provided on the upper and lower surfaces of a dielectric unit having an open side surface, and to widen the design conditions for the dielectric thin film of the thin film multilayer electrode, and the dielectric resonator A filter, a duplexer, and a high-frequency circuit device including the above are provided.
[0007]
[Means for Solving the Problems]
The present invention relates to a dielectric resonator in which thin film multilayer electrodes in which conductor thin films and dielectric thin films are alternately laminated are provided on the upper and lower surfaces of a dielectric unit with open side surfaces.
The area of each conductor thin film is extended from the upper layer to the lower layer so that the dielectric constant of the dielectric thin film is smaller than the dielectric constant of the dielectric unit, and the displacement current flowing into each layer of the conductor thin film is substantially equal. It is characterized by decreasing in order.
[0008]
In a dielectric resonator in which thin film multilayer electrodes are provided on the upper and lower surfaces of a dielectric unit with open side surfaces, when the dielectric constant of the dielectric thin film is smaller than the dielectric constant of the dielectric unit, the dielectric unit of each conductor thin film The amount of displacement current flowing from the portion exposed to the side is equal to the amount of actual current flowing through the conductor thin film. Therefore, by reducing the area of each conductor thin film in order from the upper layer to the lower layer so that the displacement current flowing into each layer of the conductor thin film becomes substantially equal, the actual current flowing through each conductor thin film becomes substantially equal, Conductor loss is minimized.
[0009]
According to the present invention, a signal input / output unit is provided in the dielectric resonator to constitute a filter.
[0010]
Further, according to the present invention, a duplexer is configured by providing two sets of the above filters and providing a transmission signal input terminal, a transmission / reception common input / output terminal, and a reception signal output terminal as signal input / output portions thereof.
[0011]
According to the present invention, a high-frequency circuit device is configured by including the dielectric resonator, the filter, or the duplexer.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The dielectric resonator according to the first embodiment will be described with reference to FIGS.
1A is a top view of a dielectric resonator, and FIG. 1B is a central longitudinal sectional view thereof. Here, 1 is a cylindrical dielectric unit. Reference numerals 2 and 3 denote thin film multilayer electrodes provided on the upper and lower surfaces of the dielectric unit. Here, an arrow loop indicated by a broken line indicates a magnetic field vector, and a white arrow indicates an electric field vector. In this way, the magnetic field rotates concentrically with the cylindrical dielectric unit, and acts as a TM010 mode resonator in which the electric field vector is oriented in a direction perpendicular to the thin film multilayer electrodes 2 and 3.
[0013]
FIG. 2 is a sectional view of a dielectric resonator in which the thickness of the thin film multilayer electrode portion is exaggerated. Here, 23 is the lowermost conductor thin film in the thin film multilayer electrode 2, and 21 is the uppermost conductor thin film. Reference numeral 22 denotes a dielectric thin film provided between the conductive thin films 23 and 21. The conductor thin film 23 and the dielectric thin film 22 each have a ring shape with a predetermined width as a planar pattern. In this way, the thin film multilayer electrode 2 is formed in which the conductor thin film 23, the dielectric thin film 22, and the conductor thin film 21 are laminated in this order.
[0014]
Similarly, 33 is the lowermost conductor thin film in the thin film multilayer electrode 3, and 31 is the uppermost conductor thin film. Reference numeral 32 denotes a dielectric thin film provided between the conductive thin films 33 and 31. The conductor thin film 33 and the dielectric thin film 32 each have a ring shape with a predetermined width as a planar pattern. In this way, the thin film multilayer electrode 3 is formed in which the conductor thin film 33, the dielectric thin film 32, and the conductor thin film 31 are laminated in this order.
[0015]
As will be described later, the area of the lower conductor thin films 23 and 33 is made smaller than that of the upper conductor thin films 21 and 31, so that the actual currents flowing in the conductor thin films of each layer are made substantially equal.
[0016]
The amount of current flowing through each conductor thin film is
[Amount of displacement current flowing into each conductor thin film] − [Amount of displacement current flowing out]
be equivalent to. When the electric flux is D and the time is t, the displacement current is (∂D / ∂t).
[0017]
Here, if the dielectric constant of the dielectric thin film is lowered below the dielectric constant of the dielectric unit to suppress displacement current exchange between the conductor thin films, the amount of displacement current flowing from a part of the conductor thin film exposed on the dielectric unit side And the amount of actual current flowing through the conductor thin film becomes equal.
[0018]
FIG. 4A shows a change in the Q of the resonator when the dielectric constant of the dielectric thin film is changed. Here, the horizontal axis represents the ratio of the dielectric constant of the dielectric thin film to the dielectric constant of the dielectric unit, and the vertical axis represents the improvement ratio of Q compared to the single layer electrode. Thus, Q improves as the dielectric constant of the dielectric thin film decreases.
[0019]
FIG. 5 shows the relationship between the position in the radius r direction from the center of the dielectric unit and the electric flux D at that position. The function Jo (r) is a cylinder function, and the electric flux distribution in the TM010 mode is proportional to the cylinder function Jo (r). The electric flux in the TM010 mode has a positive maximum at the center and a negative maximum at the periphery. Here, assuming that the central position is r0, the position where the electric flux is 0 is r2, the peripheral position is r4, the inner peripheral position of the conductor thin films 23 and 33 is r1, and the outer peripheral position is r3, the electric currents in the r0 to r1 portions. The displacement current due to the bundle and the electric flux at the r3 to r4 portions flows into the conductor thin films 21 and 31, and the displacement current due to the electric flux at the r1 to r3 portions flows into the conductor thin films 23 and 33. Therefore, if r1 and r3 are obtained in the following relationship, the displacement current flowing into the conductor thin films 23 and 33 and the displacement current flowing into the conductor thin films 21 and 31 are substantially equal.
First,
[0020]
[Expression 1]

[0021]
R1 is obtained so that the following relationship holds.
Also,
[0022]
[Expression 2]

[0023]
R3 is obtained so that the following relationship holds.
In this case, theoretically, the conductor loss is minimized and Q is maximized.
[0024]
Next, the result of simulating the characteristics of the dielectric resonator shown in FIGS. 1 and 2 is shown. FIG. 3 is a cross-sectional view of a model for simulation of the dielectric resonator. Here, one of the upper and lower surfaces of the dielectric unit 1 is a thin film multilayer electrode 2, and the other electrode is a complete conductor electrode 3 '. In such a model, the dimensions of each part were determined as follows.
[0025]
Conductor thin film 21 thickness 8.25 μm
Conductor thin film 23 thickness 1 μm
Thickness of dielectric thin film 22 0.75 μm
Dielectric constant of dielectric thin film 22 0.01 times the dielectric constant of dielectric unit (relative dielectric constant 1400))
Thickness of dielectric unit 1 (distance between conductor thin film 23 and perfect conductor electrode 3 ') 0.2 mm
Dielectric unit 1 diameter 0.5 mm
Dielectric constant of dielectric unit 1 140,000
Dielectric loss of dielectric unit 1 0 (no loss)
Conductivity of conductor thin films 22 and 23 53MS
The side surface of the dielectric unit 1 is a magnetic wall.
[0026]
FIG. 4B shows the result. Here, the horizontal axis represents the length ratio of the lower conductor thin film 23 in the radial direction with respect to the upper conductor thin film 21, and the vertical axis represents the improvement ratio of Q compared to the single layer electrode. Thus, when the radial dimension ratio of the lower conductor thin film to the upper conductor thin film is around 0.55 (around 0.5 in area ratio), Q is most improved. The “theoretical value” in the figure is the length ratio of the lower electrode in the radial direction to the upper electrode when the above [Equation 1] and [Equation 2] are satisfied.
[0027]
Next, the configuration of the dielectric resonator according to the second embodiment is shown in a sectional view in FIG. In this example, the relative dielectric constant is different between the dielectric portion 12 between the lower conductive thin films 23 and 33 and the other dielectric portion 11. Even with such a structure, if the area of each conductor thin film is determined so that the displacement current flowing into each conductor thin film becomes substantially equal, an optimum low-loss operation as a whole is possible.
[0028]
In the first and second embodiments, a thin film multilayer electrode having a three-layer structure is provided by two conductive thin films and a single dielectric thin film provided therebetween. However, three or more conductive thin films are provided. Of course, it can also be applied to other things. For example, even when configuring a thin film multilayer electrode having a five-layer structure in which three conductor thin films and two dielectric thin films are alternately stacked, the displacement current flowing into each conductor thin film is substantially equal. What is necessary is just to make small the area of each conductor thin film in order from an upper layer to a lower layer.
[0029]
In the first and second embodiments, the cylindrical dielectric unit is used. However, the shape of the dielectric unit is not limited to the cylindrical shape, and may be a quadrangular prism (rectangular) shape or a polygonal prism shape. .
[0030]
Next, the configuration of the filter according to the third embodiment will be described with reference to FIG.
In FIG. 7, the three resonators are any of the resonators shown in the first and second embodiments, and these resonators are coupled with a coupling capacitance represented by a capacitor symbol in the figure. Furthermore, the first stage and final stage resonators and the input / output terminals are coupled by a coupling capacitor to constitute a filter having a band-pass filter characteristic composed of three stages of resonators.
[0031]
Next, a configuration example of a duplexer will be described as a fourth embodiment with reference to FIG.
Here, both the transmission filter and the reception filter are filters having the structure shown in FIG. However, the respective filter characteristics are determined so that the transmission filter passes the transmission band and the reception filter passes the reception band.
[0032]
Phase adjustment is performed between the output port of the transmission filter and the input port of the reception filter so that the transmission signal does not circulate to the reception filter side and the reception signal does not circulate to the transmission filter side.
[0033]
Next, the configuration of a communication apparatus according to the fifth embodiment is shown in FIG.
Here, the duplexer is a duplexer having the configuration shown in FIG. A transmission circuit is connected to the transmission terminal of the duplexer, and a reception circuit is connected to the reception terminal. An antenna is connected to the antenna terminal.
[0034]
【The invention's effect】
According to the present invention, since a substantially equal amount of current flows through each layer of the conductive thin film in the thin film multilayer electrode in which the conductive thin film and the dielectric thin film are alternately laminated, the current concentration is alleviated and the entire conductor loss is effectively reduced. Can be suppressed. In addition, since the conductor loss is most effectively suppressed by the area (dimension and forming position) of the conductor thin film, the design conditions of the dielectric thin film portion of the thin film multilayer electrode are expanded.
[0035]
Further, according to the present invention, a filter having a small size and a low insertion loss can be obtained by providing a signal input / output unit in the resonator to constitute a filter.
[0036]
In addition, according to the present invention, two sets of the above-described filters are provided, and a duplexer is configured by providing a transmission signal input terminal, a common input / output terminal, and a reception signal output terminal as signal input / output units. A duplexer with low insertion loss can be obtained.
[0037]
According to the present invention, by configuring the high-frequency circuit device with the dielectric resonator, the filter, or the duplexer, a small-sized and low-loss high-frequency circuit can be configured, and the noise characteristics and transmission of the communication device using the same Communication quality such as speed can be improved.
[0038]
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a dielectric resonator according to a first embodiment. FIG. 2 is a cross-sectional view of the dielectric resonator. FIG. 3 is a cross-sectional view of a model for characteristic simulation of the dielectric resonator. FIG. 4 is a diagram showing an example of Q change when the dielectric constant of the dielectric thin film of the dielectric resonator is changed, and an example of Q change when the area of the conductive thin film of each layer is changed. FIG. 6 is a cross-sectional view of a dielectric resonator according to the second embodiment. FIG. 7 is a configuration of a filter according to the third embodiment. FIG. 8 is a block diagram illustrating a configuration of a duplexer according to a fourth embodiment. FIG. 9 is a block diagram illustrating a configuration of a communication device according to a fifth embodiment. Sectional view showing the configuration of the resonator 【Explanation of symbols】
1-dielectric unit 2,3-thin film multilayer electrode 3'-full conductor electrode 11,12-dielectric 21,23,31,33-conductor thin film 22,32-dielectric thin film

Claims (4)

In a dielectric resonator in which thin film multilayer electrodes in which conductor thin films and dielectric thin films are alternately laminated are provided on the upper and lower surfaces of a dielectric unit with open side surfaces,
The area of each conductor thin film is extended from the upper layer to the lower layer so that the dielectric constant of the dielectric thin film is smaller than the dielectric constant of the dielectric unit, and the displacement current flowing into each layer of the conductor thin film is substantially equal. A dielectric resonator characterized by being made smaller in order. The filter which provided the signal input-output part in the dielectric resonator of Claim 1. A duplexer comprising two sets of the filters according to claim 2 and having a transmission signal input terminal, a transmission / reception common input / output terminal, and a reception signal output terminal as the signal input / output unit. A high-frequency circuit device comprising the resonator according to claim 1, the filter according to claim 2, or the duplexer according to claim 3.

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