JPS63119303A - Dielectric resonator - Google Patents

Abstract

PURPOSE:To keep the electric equivalent length of a coupling loop constant and to change the load Q by forming a coupling element to an external circuit by a rotation type coupling loop. CONSTITUTION:A dielectric resonator consists of an enclosure 1 made from a conductor, a resonance element 2 formed with a panel-shaped block made from a dielectric, a supporting body 3 which is made from a dielectric and coaxilally supports the resonance element 2 and the enclosure 1, a resonance frequency fine adjusting element 4 made from a dielectric, and two rotation type coupling loops 51 and 52 and is excited in the TE011 mode. When a setscrew is loosened to rotate the coaxial terminal consisting of an outer conductor, an inner conductor 8, and a separator 9 around the axis, the coupling loop 51 (or 52) is rotated together with the coaxial terminal. Thus, the area of the loop surface crossing the magnetic field is changed with the length of the coupling loop kept constant to equivalently change the coupling coefficient, and the load Q is changed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a TEo 11-mod dielectric resonator suitable as a component of an antenna sharing device in, for example, a base station of a mobile phone.

The conventional technology TEa ll mode dielectric resonator has a shape and dimension of %
Although the wavelength is the same as that of a coaxial resonator, the unloaded Q is about twice as high. Also, the unloaded Q of the TEo 1t mode dielectric resonator is approximately the same as that of a rectangular waveguide resonator, but The size is approximately % of the volume of a rectangular waveguide resonator, which is much smaller.

For this reason, when comparing the TEo 11-mode dielectric resonator with a % wavelength coaxial resonator and a rectangular waveguide resonator in terms of size and electrical characteristics, the TEo 11-mode dielectric resonator is It is excellent.

However, among the conventional TEo 1t mode dielectric resonators, the resonator in which the coupling element with the external circuit is formed by a loop uses a fixed coupling loop, so it can avoid the following drawbacks. do not have.

Problems to be Solved by the Invention When changing the load Q of the TEos s mode dielectric resonator as described above, the resonator must be disassembled and replaced with a coupling loop with a different loop area, and then the resonator must be reassembled. This not only requires a lot of time and effort to disassemble and reassemble the resonator, but also avoids the inevitable change in loop length when replacing the coupling loop with a coupling loop of a different loop area. do not have.

Therefore, when constructing an antenna sharing device using such a TEOl mode dielectric resonator, for example,
Since it is not possible to determine the length of the branch line for connecting the coupling loop of the resonator to the branch point of the common line and the mounting position of the resonator, it is necessary to configure the antenna sharing device while maintaining the electrical characteristics of the resonator in the best condition. It is impossible to force it.

Means for Solving the Problems The present invention has a relatively simple structure and is characterized in that a coupling element with an external circuit is formed by a coupling loop whose loop surface is rotatable.

Function In the resonator of the present invention, when the coupling loop is rotated, the area of the loop surface intersecting with the magnetic field changes while the length of the coupling loop is kept constant, and the coupling coefficient changes equimetrically. The load Q corresponding to the reciprocal of the coupling coefficient will change.

Embodiment FIG. 1 is a sectional view (B in FIG. 2) showing an embodiment of the present invention.
-B cross-sectional view), Figure 2 is the A-A cross-sectional view of Figure 1, and in both figures, l is the casing (shield case) made of a conductor.
, 2 is a resonant element consisting of a plate-shaped block, which is made of a dielectric material with high Q and dielectric constant and good temperature characteristics. Reference numeral 3 denotes a support body for the resonant element 2, which is made of a material having a high Q, a much lower dielectric constant than the resonant element 2, and stable temperature characteristics, such as quartz glass. The other end is fixed to the inner wall of the casing 1, so that the resonant element 2 is coaxially supported approximately at the center of the casing 1. Reference numeral 4 designates a resonant frequency fine adjustment element, which is made of substantially the same material as the resonant element 2, and has a screw portion 4I screwed onto the wall surface of the casing l; It consists of a plate-shaped part 42 attached to the inner end of the resonator 41 and opposed to the board surface of the resonant element 2, and a lock nut 43. By rotating the screw part 41 in forward and reverse directions, the plate-shaped part 42 can be finely divided. It is formed so that it can be moved forward and backward. 51 and 52 are coupling loops, and 61 and 62 are coupling terminals, respectively, for example, the third
It is formed as shown in the enlarged cross-sectional view in the figure.

In Fig. 3, 1 is a housing, 7 is an outer conductor, 8 is an inner conductor, and 9 is a separator made of an insulator. 61 and 62), and the base of the external conductor 7 is rotatably inserted into the mounting hole bored in the housing l. Reference numeral 10 denotes a ring-shaped holding fitting, which is provided on the outer circumferential surface of the base of the external conductor 7 in a groove-shaped portion formed by the circumferential step provided on the inner circumferential surface and the outer wall surface of the housing 1. The flanges are formed so that they fit loosely. Combined loop 5
One end of 1 (and 52) is fixed to the inner end of the internal conductor 8 using a screw 11 or by explosive bonding, etc., and the other end is fixed to the base of the outer conductor 7 by explosive bonding, screwing, etc. It is fixed by Reference numeral 12 denotes set screws, and a plurality of screws (for example, three or four screws) are inserted at appropriate intervals in the circumferential direction of the ring-shaped presser fitting 10 into insertion holes provided in the ring-shaped presser fitting 10. , and is screwed into a screw hole provided in the wall of the casing l corresponding to this insertion hole.

When the set screw 12 is loosened and the coaxial terminal consisting of the outer conductor 7, inner conductor 8 and separator 9 is rotated around the central axis, the coupling loop 51 (or 52) also rotates together with the coaxial terminal, When the set screw 12 is tightened, the circumferential step provided on the inner peripheral surface of the ring-shaped presser fitting 10
The coupling loop 5+ (or 52) and the coaxial terminal are fixed at any desired angular position by being crimped onto a flanged protrusion protruding from the outer peripheral surface of the base of the external conductor 7.

4 and 5 are diagrams showing the electromagnetic field distribution of the resonator of the present invention shown in FIGS. 1 and 2. FIG. 4 is a schematic cross-sectional view corresponding to FIG. 1, and FIG. teeth.

A schematic cross-sectional view corresponding to FIG. 2, where the solid line with an arrow in FIG. 4 and the solid line in FIG. 5 indicate the electric field distribution,
The dashed lines with arrows in both figures indicate the magnetic field distribution.

Since the resonator can be coupled to an external circuit by providing a coupling loop so that the magnetic field vector shown in FIGS. 4 and 5 intersects with the loop plane, the coupling loop is attached at a location other than that shown in FIG. 2. The invention can also be implemented by providing coupling loops on the side walls or on the shorting walls.

Incidentally, the two sets of coupling loops 51 and 52 and the coupling terminals 61 and B2 may both be provided on the side wall or shorting wall of the resonator.
Either one set may be provided on the side wall, and the other set may be provided on the short-circuit wall.

When the coupling loop (5+ or 52 or 51 and 52) and coupling terminal (8+ or 62 or 6I and 82) are provided on the short-circuit wall of the resonator, the loop plane is perpendicular to the radial direction of the resonator and parallel to the central axis direction. By smoothing, the coupling coefficient can be maximized, and the magnitude of this maximum coupling coefficient varies depending on the installation location of the coupling loop and coupling terminal, that is, the radial distance from the central axis of the resonator to the installation location. However, the load Q can be determined by the reciprocal of the coupling coefficient.

When the coupling loop (51 or 52 or 51 and 52) and the coupling terminal (61 or 82 or 81 and 82) are provided on the side wall of the resonator, the coupling loop (51 or 52 or 51 and 52)
The coupling coefficient can be maximized by making the center position of 1 and 52) at a point within approximately the inner diameter of the resonator from the side wall and making the loop surface perpendicular to the central axis direction of the resonator.
Although the magnitude of this maximum coupling coefficient varies depending on the installation location of the coupling loop and coupling terminal, that is, the position in the central axis direction of the resonator, the load Q can be determined by the reciprocal of the coupling coefficient.

As mentioned above, when the coupling loop and the coupling terminal are provided on the short wall of the resonator, the coupling coefficient is maximum when the loop plane is perpendicular to the radial direction, and the coupling loop and the coupling terminal are provided on the side wall of the resonator. When provided, the coupling coefficient is maximum when the loop surface is perpendicular to the central axis direction, but in either case, by rotating the coupling terminal and coupling loop, it is possible to Since the area can be changed, the load Q of the resonator can be set to a required value by adjusting the rotation angle while measuring the load Q using an appropriate measuring device.

Figure 6 is a curve diagram depicting the relationship between the rotation angle of the coupling loop and the coupling coefficient based on actual measurements. It's Toshide. The vertical axis is the coupling coefficient.

The loop area when the rotation angle of the loop surface is 06 is A
o, and when the loop surface is rotated by an arbitrary angle θ, and the equivalent area of the loop when looking at the loop surface from the magnetic field direction is Ao, As = Ao-cosθ −−−−(
1) When the rotation angle of the loop surface is 06, the number of magnetic fluxes that intersect with the loop surface is φ0, the coupling coefficient at this time, that is, the maximum coupling coefficient is ko, and when the loop surface is rotated by an arbitrary angle θ, the loop If the number of intersecting magnetic fluxes is φe, the number of intersecting magnetic fluxes is proportional to the equivalent area of the loop, so θ is the coupling coefficient when the loop surface is rotated by an arbitrary angle θ, ks = ko -cosθ ・---(
4) Let QLO be the load Q on the resonator when the rotation angle of the loop plane is 06, and let QLO be the load Q on the resonator when the loop plane is rotated by an arbitrary angle θ, then QLO=-...・(5) As is clear from equation (6), the rotation angle θ of the loop surface is 80
When the angle is .degree., the load Q becomes infinite.

That is, by rotating the loop plane from 0° to 80°, the load Q of the resonator can be changed from QLO to infinity.

Therefore, in order to set the load Q of the resonator to a desired value, for example, in the design stage, if the rotation angle of the loop surface is approximately 45 degrees, the shape and dimensions of the loop must be adjusted so that it approximately matches the desired value of the load Q. After determining this and assembling the resonator, the loop surface is slightly rotated back and forth around a rotation angle of 45'' to match the desired load Q, thereby creating a resonator with the desired load Q. can be formed.

In the resonator of the present invention configured as described above, the dimensions of the housing 1 and the resonant element 2 are determined according to the cutoff frequency, and the screw portion 41 of the resonant frequency fine adjustment element 4 is finely rotated in forward and reverse directions. By making it possible to resonate with a desired high-frequency signal and finely adjusting the rotation angles of the coupling loops 51 and 52 to match the required load Q, the electromagnetic field distribution as shown in FIGS. 4 and 5 is obtained. Since it is possible to excite the TEo1+ mode and make it resonate, and to make the electrical length of the coupling loops 51 and 52 constant when looking into the resonator from the coupling terminal 81 or 82, it can be used, for example, as a component of the antenna sharing device described later. When used, its design and manufacture can be facilitated.

Although the case has been described above in which the casing l is formed using a bottomed cylinder with a circular cross section, the present invention can also be practiced even if it is formed using a bottomed cylinder with a square cross section.

Moreover, the above is the connection terminal 8. and 82 are formed using coaxial terminals, but they may be formed using a suitable connector instead of the coaxial terminals.

FIG. 7 is a diagram showing an example of an antenna sharing device constructed using the resonator of the present invention, in which CL is a common line, which is composed of a coaxial line such as a coaxial tube or a coaxial cable.

Pl to Pn (n is any positive integer) are branch points, and the interval between each branch point is selected to be g72 (g is the wavelength in the pipe).

CAV! Cavn to cavn are the resonators of the present invention explained with reference to FIGS. The length of the lines BLI to BLn including the length of the coupling loop in each resonator is λg/4.
has been selected.

Incidentally, the branch lines BLI to BLn are similar to the common line CL,
Each of them consists of a coaxial line such as a coaxial tube or a coaxial cable, and a transmitter or a receiver is connected to the coupling terminals TI to Tn of each other of the resonators CAV to CAVn, and a common antenna is connected to one end TA of the common line CL. is connected.

When looking from an arbitrary branch point Pk to the resonator CAVk side of the present invention, the combined length of the branch line BLk and the length to the terminal (ground point) of the coupling loop in the resonator CAVk is λ
g/4, at the non-resonant frequency of the resonator CAVk, the impedance seen from the branch point Pk toward the resonator CAVk becomes a high impedance, and exhibits a characteristic impedance at the resonant frequency.

FIG. 8 shows the branch line BLk and the resonator C in FIG.
The equivalent circuit of the circuit part consisting of AVk, where Xk is the circuit resistance, rk is the circuit resistance, Pk is the branch point, and T
k is a connection terminal of the transmitter or receiver.

If the unloaded Q of the resonator cavt+ is Quk and the load QeQu, then the resistance molecule 1. And the reactance Xk is expressed by the following formula: % fok: Resonant frequency of resonator CAVk: Any frequency The basic matrix of the equivalent circuit shown in Fig. 8 is...
(9) It is expressed as

However, 2=rk+j2Xk When terminal Tk in FIG. 8 is terminated with a resistor (R=Zo) equal to the characteristic impedance, the admittance 9 seen from the branch point Pk to the resonator CAh side is expressed as follows.

Figure 9 shows the connection from the antenna connection terminal T^ in Figure 7 to the common line O.
In the equivalent circuit diagram when looking at the resonator CAV to cavn side through L, 'fl to tn represent the resonator CAV to CA
This is the admittance of each resonator circuit when each transmitter or receiver connection terminal TI to Tn of Vn is terminated with a resistor equal to the characteristic impedance, and other symbols are the same as in FIG. 7.

The mutual spacing between the branch points pl to Pn in FIG. 9 is 8/
2, therefore, FIG. 9, and therefore FIG.
It can be rewritten as shown in diagram O.

As is clear from FIGS. 9 and 10, the admittance Ypk at any branch point Pk can be directly determined from the following equation.

The voltage reflection coefficient rpk at the common antenna connection terminal TA can be obtained from equations (11) to (12), and the reflection loss Lpk at the terminal TA can be obtained from equation (13).

However, Yo: Characteristic admittance of the common line CL, and equation (12) applies when Yo=1.

Lpk = 20JLoi l Tpk I
・ ・ ・ ・ (13) Admittance yk of resonator CAh connected to arbitrary branch point Pk
is expressed as from equation (11), and the conductance of admittance tk is Gk
Then, at the resonant frequency, it becomes... (15).

That is, the conductance has a value close to 1.

Also, at non-resonant frequencies, the normalized susceptance Xk
becomes .

That is, the susceptance is extremely small.

Therefore, the resonator CA connected to any branch point Pk
The equivalent circuit of Vk is a circuit equivalent to a parallel resonant circuit connected to a branch point via a λg/4 line as shown in FIG.

Also, among the connection terminals T1 to Tn of the transmitter or receiver in FIG. 7, any terminal Tk to the common antenna connection terminal T
The equivalent circuit up to A can be expressed as shown in FIG.

The basic matrix of the circuit shown in FIG. 12 is, however, It is expressed as

The input admittance yk^ at any terminal Tk when the terminal T^ is terminated with a non-reflection terminator R is (17
), the voltage reflection coefficient i at terminal Tk can be obtained from the equation (18).
'u becomes, and the reflection loss Lrk^ at terminal k is Lrb
A=201oq l'LAI...(2
0).

The transmission characteristic LkA between the terminals Tk and 74 is obtained from the equation (17) using the following equation.

・ ・ ・ ・ (21) FIG. 13 is an equivalent circuit diagram for determining the inter-terminal coupling between arbitrary terminals 'rs and Tn among the connection terminals TI to tn of the transmitter or receiver in FIG. The admittance and tn of the resonators CAVn and CAVn can be determined by equations (22) to (27), where conductance is G- and cn, and susceptance is bl and bn.

Ym = Ga + j bs ・
... (22)b11=2Xs Yn=Gn+jbn HHHH(2
5) bn ” 2Xn Qus ; No-load QQLs of resonator cavs: Resonator CAVs (7) Load QQun: Resonator CAV
No load QQLn of n: Load Q f's of resonator cavn: Resonant frequency fan of resonator CAV-:
The resonant frequency of the resonator CAVn can be calculated by calculating the composite admittance of the circuit shown in Figure 13 from the composite admittance of the resonator CA
Since it is obtained by subtracting the admittance of VI and GAVn and Yn, it can be calculated as follows.

When the basic matrix between terminals Ts and Tn in FIG. 13 is obtained from equations (22) to (28),...
(29) becomes.

Further, the coupling attenuation amount Lln between the terminals TI and Tn is obtained by the following equation.

FIG. 7 shows an example in which one resonator cavt to cavn is branch-connected to each branch point P1 to Pn of the common line CL, but as shown in FIG. 14, each branch point P
Branch lines BL+t, BLI 2, BL21 from 1 to Pn
, BL22 to BLn 1, BLn 2 via two resonators CAVt 1, CAV12, CAV21.
, CAV22 to CAVni, and CAVn2 may be branch-connected, and three or more resonators may be branch-connected to each branch point to form a shared device.

In the case where a plurality of resonators are branch-connected to each branch point of a common line, the interval between each branch point of the common line is selected to be λg/2, and the distance between each branch line Of course, the length is chosen to be λg/4, including the length of the coupling loop in the resonator.

Effects of the Invention In the resonator of the present invention, the coupling element with the external circuit is formed by a rotating coupling loop, so by rotating this, the equivalent area of the loop that intersects with the magnetic field is changed, and the load Q is changed. Even when the resonator of the present invention is used to construct an antenna sharing device, the length of the coupling loop does not change and the electrical quality of the coupling loop can be kept constant. Its design and manufacture become extremely easy.

The actual measured values of the electrical characteristics of the prototype manufactured by the present inventors agreed extremely well with the results of the above-mentioned theoretical calculations, and the electrical characteristics of the antenna sharing device prototyped using the same were also extremely good.

FIG. 15 is a curve diagram showing an example of the transmission characteristics of a prototype of the antenna sharing device.
The actual measured value of the channel, the horizontal axis is the transmission frequency f (MHz
), the vertical axis is the transmission loss L (dB), and as is clear from the figure, the insertion loss of the antenna sharing device constructed using the resonator of the present invention is extremely small.

FIG. 18 is a curve diagram showing an example of the return loss characteristics of the prototype of the antenna sharing device.
Actual measurement values for 8 channels in the 0 MHz band. The horizontal axis is the transmission frequency f (MHz), and the vertical axis is the return loss Lr (dB) at the shared antenna connection terminal. The return loss is large for each channel, and the matching is good. It shows that.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing one embodiment of the present invention,
FIG. 3 is an enlarged cross-sectional view showing the main elements thereof, FIGS. 4 and 5 are cross-sectional schematic diagrams showing the electromagnetic field distribution of the resonator of the present invention, and FIG. 6 is a main part of the resonator of the present invention. 7 and 14 are curve diagrams for explaining the operation of the element, and FIGS. 7 and 14 are diagrams showing an antenna sharing device constructed using the resonator of the present invention, and FIGS. 8 to 13 are curve diagrams for explaining the operation. Equivalent circuit diagram, 15th
16 and 16 are characteristic curve diagrams of an antenna sharing device constructed using the resonator of the present invention, in which 1: housing, 2: resonant element,
3: Resonant element support, 4: Resonant frequency fine adjustment element, 4-domain screw part, 42: Plate-shaped part, 43: Lock nut, 51 and 52: Coupling loop, 61 and 82: Coupling terminal, 7: External conductor , 8: internal conductor, 9: separator, 10
: Ring-shaped presser fitting, 11 and 12: Set screw, CL
: common line, Pl to Pn: branch point, cavt to CA
Vyl, CAVII, CAVX2 to CAVn l
, CAVn2: resonator of the present invention, BLI to BLn,
BLIt, BLI2 to BLn 1, BLn2: Branch line, T! to Tn: transmitter or receiver connection terminal, D: common antenna connection terminal.

Claims (5)

[Claims] (1) A resonance element made of a casing made of a conductor, a plate-shaped block made of a dielectric, a support made of a dielectric that supports the resonant element coaxially with the casing, and a resonance made of a dielectric. A dielectric resonator comprising a frequency fine adjustment element and two rotary coupling loops, and characterized in that a TE_0_1_1 mode is excited. (2) A rotary coupling loop has an outer conductor whose base is rotatably inserted into a hole bored in the housing wall, and an inner part arranged coaxially with the outer conductor via a separator made of an insulator. A conductor, a ring-shaped holding fitting provided on the outer periphery of a flanged projection protruding from the outer periphery of the base of the external conductor and having a stepped portion on the inner peripheral surface, and a hole drilled in the ring-shaped holding fitting. a screw that is screwed into the housing through the screw and loosely or firmly fixes the outer conductor between the ring-shaped holding fitting and the housing; one end is attached to the inner end of the inner conductor, and the other end is attached to the outer A dielectric resonator according to claim 1, wherein the dielectric resonator is formed by loops each attached to a base of a conductor. (3) A dielectric resonator according to claim 1, wherein the two rotary coupling loops are provided on the short-circuit wall of the housing. (4) The dielectric resonator according to claim 1, wherein the two rotary coupling loops are provided on the side wall of the casing. (5) The dielectric resonator according to claim 1, wherein one of the rotary coupling loops is provided on the short-circuit wall of the casing, and the other rotary coupling loop is provided on the side wall of the casing.