DE102010044267B4 - compensation unit - Google Patents

Abstract

Device for waveguides, in particular for use as output filter in multiplexers, consisting of an upwardly partially open resonator (4) with a compensation unit (3) on which an axially freely movable metallic or metallized compensation plate (1) is arranged, wherein the Compensation actuator (1) by means of a pin (2, 6) by the compensation unit (3) is axially displaceable; characterized in that the compensation unit (3) is a bimetal or a material with a higher coefficient of expansion than the resonator (4) and is designed to exert a force on the at least one pin (2; 6) by thermal expansion and displace it.

Description

State of the art

The invention relates to a compensation unit for tuning high-power resonators to compensate for changes in the resonator frequency.

The changes in the resonator frequency are caused by changes in the resonator temperature. To provide sufficient thermal stability, output filters for use in multiplexers over a wide temperature range should have as much constant bandwidth and center frequency as possible. In operating environments in which a large temperature change is to be expected, due to the changes in the structural dimensions due to the thermal expansion, a strong drift of the center frequency and thus the electrical properties can occur. The resonator frequency varies in inverse proportion to the operating temperature and the linear expansion coefficient of the material used to make the resonators.

Known are Invar filter trains whose thermal expansion is very low at 1 ppm, but the high mass and poor thermal conductivity of Invar are disadvantageous.

It is therefore desirable to build an output filter made of aluminum. For this, however, the temperature expansion of aluminum must be compensated by 23 ppm. If the compensation only affects the resonator length, the extension of the resonator diameter must also be compensated by a greater change in length.

For applications in Ku-band solutions for temperature-compensated aluminum filters have already been developed in which a thin aluminum membrane is deformed by a bimetal directly or via a lever mechanism. Compensation can also be achieved by utilizing the temperature dependence of the dielectric constant or the expansion of a dielectric.

In the DE 36 88 158 T2 For example, a "Metallic Microwave Cavity Resonator" is disclosed. This is a metallic microwave cavity resonator with a temperature equivalent, wherein a movable metal sheet is disposed within a first hollow body, which closes the cavity and allows a tuning control of its resonator frequency. The volume of the microwave cavity resonator remains constant despite the mechanical deformation by the expansion of the walls of both hollow body by the vote of the wall thickness and the thermal expansion coefficient of the two hollow bodies in the final result. For the production of the cavity resonator aluminum is used, which is particularly suitable for installation on board because of its low specific weight. This has the disadvantage that mechanical stress arises as a result of the mechanical bending, in addition the quality (Q) is reduced by the conical resonator shape.

Also known is a "cavity with temperature compensation" ( DE 692 09 223 T2 ) with a compensation plate which is mounted between the upper end of the Resonatorinnenleiters and the top of the resonator. The middle part of this compensation plate is pressed by the fact that the thermal expansion coefficient of the plate is smaller than that of the top, with a temperature rise to the top. This coax resonator has the disadvantage that it has a much lower quality and that the compensation leads to mechanical stress.

It is further on the pamphlets US 2 716 222 A . EP 1 187 247 A2 and US 2006/0 132 263 A1 directed.

The invention and its advantages

The invention according to the features of the main claim, however, has the advantage that the electrical decoupling of the resonator from the compensation unit is independent of how the temperature compensation, ie the change in length of the resonator over temperature, is realized itself. Because of its special properties, the solution according to the invention is advantageous for resonators for power output filters, in particular for TE01n resonators. Although there is already some ground decoupling due to the field distribution of the TE01n mode, the energy coupled upwards leads to an increase in the power loss and thus to heating. Here, the invention begins to improve the electrical decoupling by the measures described, in particular under the proviso of a good thermal connection of the lid.

According to an advantageous embodiment of the invention, there is no galvanic contact between the resonator and the resonator. In contrast to the known solutions of a closed resonator with a thin membrane of compensation plate is suspended by a pin axially freely movable on a compensation unit. This compensation unit makes it possible to shift the compensation plate depending on the temperature so that the temperature-induced change in the resonance frequency is compensated. The necessary stroke for compensation can be generated for example by a bimetal or by a material with a higher coefficient of expansion.

An advantage of the invention is that due to the free suspension of the lid in the axial direction, the compensation unit has to apply only small force in order to achieve the displacement required for compensation and the compensation does not generate any mechanical tension. The compensation of the resonance frequency is achieved by the movement of the metallic or metallized plate in the resonator chamber.

The inventive upwardly partially open resonator must be electrically decoupled against the compensation unit. This is done according to an advantageous embodiment of the invention in that the metallic compensation plate is connected via a metallic pin with the compensation unit. The compensation pin is easy to move and has no galvanic contact with the resonator housing. The area above the compensation actuator thus acts like a coaxial line with the connecting pin as an inner conductor. The resonator is thus decoupled from the compensation unit with a decoupling structure suitable for coaxial structures with characteristic impedance jumps of the inner or outer conductor.

In addition, good thermal coupling between the compensation plate and the resonator housing has to be ensured in order to be able to dissipate the power dissipation that occurs at the compensation plate. According to the invention, this heat loss is dissipated via the metallic connecting pin. The diameter of the pin is chosen so that the heat generated by the power loss is dissipated. If this is not possible with a pen, you can use multiple pens.

According to another advantageous embodiment of the invention, the metallic or metallized compensation plate is connected via a dielectric pin to the compensation unit. The area above the compensation actuator thus acts like a dielectric filled waveguide. To decouple the resonator from the compensation unit of the waveguide cross-section is reduced above the compensation actuator so that the useful frequency of the filter is smaller than the cutoff frequency of the waveguide. When calculating the cutoff frequency, the dielectric constant of the dielectric pin has to be considered.

According to an advantageous embodiment of the invention, the very good thermal conductivity of the selected dielectric ensures good thermal contact. For example, aluminum nitride (ε _τ = 9.2) or beryllium oxide (ε _τ = 6.5-7.5) are used for this purpose. If the thermal coupling of a pen is not sufficient, several pins can be used, taking into account the cutoff frequency.

Especially at very high power, the heat flow through the pin into the bimetal in the compensation unit can cause the bimetal to heat up more than the filter housing. This can lead to overcompensation of the relevant resonator and thus to a mismatch of the filter frequency. For this case, it is provided to modify the above-described good thermal coupling of the bimetal, such that the power loss arising at the compensation actuator is not or not only directly discharged via the pin and the compensation unit to the filter housing, but via a parallel path. The thermal conductivities of the pin and the parallel path are selected so that the effective temperature applied to the bimetal during operation corresponds to the temperature of the filter housing. This ensures that the resonant frequency of the filter is effectively compensated for both power and non-powered operation.

Since the compensation actuator must be axially freely movable, care must be taken in the realization of the parallel path that this does not restrict the movement of the compensation actuator. In addition, its thermal conductivity must be sufficiently high to thermally dissipate the power dissipated in the compensation actuator together with the path across the pin and the compensation unit. For the realization of the parallel path, for example, highly flexible copper strips or copper braids in question. These must be attached to the resonator housing and the compensation plate with good thermal conductivity.

The above-described electrical decoupling of the resonator from the compensation unit must be ensured even when dissipating the power loss over a parallel path.

As an alternative to the above-described heat dissipation by means of copper tapes or braid can also after a highly flexible metallic fold membrane after 9 be provided for a full surface heat dissipation.

Due to the inventive design of the filter this has very good thermal properties, has a low mass and is easy to manufacture. Due to the type of suspension according to the invention, the compensation unit must apply significantly less force in order to achieve the Resonatorverkürzung required for compensation. Thus, an embodiment of the compensated filter is achieved, that of a filter with closed Resonators of temperaturinvariantem and good thermally conductive material corresponds, however, in contrast, has the advantages mentioned above.

Further advantages and advantageous embodiments of the invention are the following description, the drawings and claims removed.

list of figures

• 1 zeigt einen Resonator mit Koax-Entkopplung;
• 2 stellt einen Resonator mit Koax-Entkopplung und mehrere Durchführungen dar;
• 3 zeigt einen Resonator mit dielektrischer Entkopplung;
• 4 zeigt einen Resonator mit dielektrischer Entkopplung und mehreren Durchführungen;
• 5 zeigt einen alternativen Pfad zur Temperaturkompensation;
• 6 zeigt die Anordnung von 5 mit mehreren metallischen Stiften;
• 7 zeigt eine Anordnung mit einem dielektrischen Stift;
• 8 zeigt eine Anordnung mit mehreren dielektrischen Stift;
• 9 zeigt eine weitere Anordnung eines thermischen Pfads nach 5.

Embodiments of the subject invention are illustrated in the drawings and are explained in more detail below.

• 1 shows a resonator with coax decoupling;
• 2 illustrates a resonator with coax decoupling and multiple feedthroughs;
• 3 shows a resonator with dielectric decoupling;
• 4 shows a resonator with dielectric decoupling and multiple feedthroughs;
• 5 shows an alternative path for temperature compensation;
• 6 shows the arrangement of 5 with several metallic pins;
• 7 shows an arrangement with a dielectric pin;
• 8th shows an arrangement with a plurality of dielectric pin;
• 9 shows a further arrangement of a thermal path 5 ,

Description of the embodiments

1 shows a metallic compensation plate 1 that has a metallic pin 2 , which has a good thermal conductivity, and with the compensation unit 3 connected is. The compensation pen 2 must be axially smoothly movable and therefore has no galvanic contact with the housing of the resonator 4 , The area above the compensation controller 1 acts as a coaxial line with the connecting pin 2 as an inner conductor. The resonator 4 So it must have a decoupling structure suitable for coaxial structures 5 with characteristic impedance jumps of the inner or outer conductor of the compensation unit 3 be decoupled. The resulting heat loss is via the metallic connecting pin 2 dissipated. The diameter of the pin 2 is chosen so that the resulting power can be dissipated.

In 2 is the metallic compensation plate 1 , the metallic pins 2 and the compensation unit 3 and the resonator 4 shown. The pins 2 are accomplishments 5 assigned. By two or more pins more heat loss can be dissipated and at the same time a greater mechanical stability of the leadership of the compensation actuator 1 reached.

In 3 are the metallic compensation plates 1 and the compensation unit 3 and the resonator 4 shown, wherein the compensation plate 1 over a dielectric pin 6 with the compensation unit 3 connected is. The area above the compensation controller 1 acts like a dielectric filled waveguide. For decoupling of the resonator 4 from the compensation unit 3 the waveguide cross-section must be reduced so that the useful frequency of the filter is smaller than the cutoff frequency of the waveguide. When calculating the cutoff frequency, the dielectric constant of the dielectric pin is 6 to take into account.

4 shows the compensation plate 1 , the dielectric pin 6 with good thermal conductivity, the dielectric decoupling structure 7 under cutoff as well as the compensation unit 3 and the resonator 4 , If the required diameter is too small to provide sufficient thermal contact and heat dissipation, multiple feedthroughs, each under cutoff, must be used. Good thermal contact is ensured by the very good thermal conductivity of the chosen dielectric. For example, aluminum nitride (ε _τ = 9.2) or beryllium oxide (ε _τ = 6.5-7.5) are suitable for this purpose.

5 shows an embodiment of the invention according to 1 , that at very high performance the resulting power loss not or not only by the pen 2 in the compensation unit 3 dissipates, causing the bimetal of the compensation unit 3 is heated too high, so that it can lead to overcompensation of the resonator with a corresponding mismatch of the filter frequency. In this case, a modification of the heat dissipation in the compensation controller 1 accumulating heat loss provided via an alternative path. By means of the alternative path, the heat loss from the compensation actuator 1 over one or more copper bands or - a copper braid 5a in the resonator housing 4 be dissipated.

In the 6 illustrated embodiment corresponds largely to in 2 shown arrangement, with the difference that an additional path of heat dissipation from the compensation controller 1 on the resonator housing 4 by means of the adapted heat dissipation elements 5a to 5 he follows.

7 shows a compensation device after 3 , in addition, a heat dissipation from the compensation actuator 1 via a parallel path by means of the above-described highly flexible copper strips or copper braids. Again, the heat loss from the compensation actuator 1 by means of flexible copper strips or copper braid 5a to the resonator housing 4 dissipated.

8th represents a modification of in 4 illustrated embodiment, in which also an alternative path for deriving the compensation in the controller 1 resulting heat by means of flexible heat-conducting elements 5a he follows.

In 9 is an alternative embodiment to the flexible copper bands or copper braid 5a shown; Here comes a highly flexible pleated membrane 8th made of thermally conductive material used on the one hand with the compensation plate 1 and on the other hand is in heat-conducting contact with the resonator housing. This is indicated by the wrinkle membrane 8th a cup-shaped inner part 9 on, in thermally conductive contact with the compensation plate 1 stands. From the inner part 9 extends radially outwardly an annularly folded membrane 10 coming from an outer edge 11 is limited and with a to the resonator lid 12 fitted collar 13 in thermal contact. In this way, a full-surface heat dissipation of the compensation plate can be 1 on the resonator housing 4 to reach.

Does the wrinkled membrane exist? 8th made of electrically conductive material, a galvanic isolation between the compensation plate 1 and the pleated membrane 8th through a between the bottom of the inner part 9 the diaphragm and the compensation actuator 1 arranged insulating mica washer 15 reached.

The bottom of the inner part 9 is according to the arrangement of the pins 2 ; 6 provided with one or more holes whose diameter is greater than the diameter of the pin or pins 2 ; 6. Furthermore, the wrinkle membrane 8th an opening 14 for pressure equalization.

All in the description, the following claims and the drawings illustrated features may be essential to the invention both individually and in any combination.

LIST OF REFERENCE NUMBERS

1

compensation plate

2

metallic pin

3

compensation unit

4

resonator

5

Decoupling structure (coaxial)

5a

Copper bands or copper braid

6

dielectric pin

7

dielectric decoupling structure

8th

fold membrane

9

cup-shaped inner part

10

membrane portion

11

Edge of the inner part

12

outer edge of the pleated membrane

13

collar

14

opening

15

Glimmerunterlegscheibe

Claims (14)

Device for waveguides, in particular for use as output filter in multiplexers, consisting of an upwardly partially open resonator (4) with a compensation unit (3) on which an axially freely movable metallic or metallized compensation plate (1) is arranged, wherein the Compensation actuator (1) by means of a pin (2, 6) by the compensation unit (3) is axially displaceable; characterized in that the compensation unit (3) is a bimetal or a material with a higher coefficient of expansion than the resonator (4) and is designed to exert a force on the at least one pin (2; 6) by thermal expansion and displace it. Device after Claim 1 , Characterized in that the at least one pin (2) is metallic. Device after Claim 1 , characterized in that the at least one pin (6) is dielectric. Device after Claim 2 or 3 , characterized in that the compensation plate (1) via the pin (2, 6) is connected to the compensation unit (3). Device after Claim 3 , characterized in that the waveguide cross-section is designed so that the useful frequency of the filter is smaller than the cutoff frequency of the waveguide. Device after Claim 3 , characterized in that the dielectric pin (6) consists of aluminum nitride or beryllium oxide. Device after Claim 1 , characterized in that the output filter is a TE01n resonator. Device after Claim 2 , characterized in that the diameter of the at least one pin (2; 6), which serves for the thermal coupling between the compensation plate (1) and compensation unit (3), is adapted to the amount of heat to be dissipated. Device according to one of the preceding claims, characterized in that at least two pins (2; 6), for thermal coupling between the compensation plate (1) and compensation unit (3) are arranged. Device according to at least one of the preceding claims, characterized in that for discharging the loss heat generated in the compensation plate (1) via the pin (2; 6) to the compensation unit (3) a parallel path (5a) bypassing the compensation unit (3) is provided is. Device after Claim 10 , characterized in that the thermal conductivities of the two paths are designed such that when operating with power, the temperatures of the compensation unit (3) and the resonator (4) correspond. Device according to at least one of the preceding claims, characterized in that two or more pins (2; 6) are provided to achieve the required thermal conductivity, with simultaneously improved mechanical stability. Device according to at least one of the preceding claims, characterized in that the pin (2; 6) for thermal coupling and electrical decoupling of dielectric or metallic material (aluminum, copper) with good or poor (titanium, stainless steel) conductivity. Device after Claim 10 and / or 11, characterized in that the parallel path (5a) for loss of heat dissipation by means of a pleated membrane (8) made of thermally conductive material, with the compensation plate (1) in good thermal conductivity, electrically isolated connection (6, 15) and with its collar (13) is thermally conductively connected to the resonator housing.

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