EP1132996A1 - Filter or multicoupler type arrangement with an electronically tunable resonator - Google Patents

Abstract

The electronically tuneable filter or multicoupler has a switching element connected to an electronically tuneable element. There is a quarter wave coaxial resonator (1) with a central unit (2). The tuning mechanism (5) is mounted directly on the side of the central unit.

Description

The invention relates to an arrangement of the filter type. or multicoupler, comprising a resonator electronically tunable by a tuning device which has at least one element of agreement, an element of switching to connect the tuning element selectively electrically to said resonator and a device for switching element control.

Arrangements of this type are already known. he however, it turned out that the known devices do not can simultaneously realize wide tuning bands in frequency, high power operation, very low electronic tuning time and losses reduced insertion times. They are such that mounting between the different components of a device okay requires soldering contact wires and that their assembly is problematic, especially in due to mechanical tolerances and expansions between the different elements. These problems increase with increasing band tuning frequency and the number of tuning elements necessary for this purpose.

The object of the present invention is to provide a arrangement which overcomes the disadvantages which come to be stated.

To achieve this goal, a tunable arrangement according to the invention is characterized in that it comprises a coaxial resonator, of the quarter wave type, of which the central organ constituting the line has a shape cylindrical with the upper surface serving as a surface for fitting tuning devices.

According to a characteristic of the invention, the different components of a device okay, that dissipate energy and have a drain different heaters are removable.

According to another characteristic of the invention, the aforementioned elements are kept in contact mechanical and electrical in the tuning device under the effect of pressure forces, advantageously spring.

According to another characteristic of the invention, the PIN diode and tuning capacity are connected in series between a top plate of the resonator and the body forming the line, the diode being fixed removably by its case to said plate and the ability to agree being removably attached to the body and both being electrically interconnected in series by a washer elastic.

According to yet another characteristic, the housing of the PIN diode has a threaded end for cross the upper ground plate and is provided a support shoulder against the internal face of the plate under the tightening effect of a nut screwed on the nozzle on the other side of the plate.

According to yet another characteristic of the invention, the tuning capacity includes a support provided with a threaded end that can be screwed into the upper face of the body forming the line.

According to yet another characteristic of the invention, the PIN diode rests on a front face of the elastic washer whose other face is at contact of a support based on the capacity of agreement.

According to yet another characteristic of the invention, the ability to agree comprises a plurality power capacities paralleled and welded in the aforementioned screwable support.

According to yet another characteristic of the invention, the electrical contact between the device for controlling a PIN diode and the commanded PIN diode is formed by a contact element made in the form a spring rod, one end of which is connected to a self of the control circuit while the other end is pressed under the effect of a spring against the support of the aforementioned washer.

According to yet another characteristic of the invention, the upper mounting surface of the tuning devices is adapted to allow the mounting of a greater number of tuning devices than that strictly necessary for the achievement of no frequency, in order to be able to increase either the number of chord steps, either the maximum power or both again.

• la figure 1 est une vue latérale schématique d'un résonateur à cavité coaxiale selon l'invention ;
• la figure 2 est une vue éclatée de la partie indiquée par la flèche II sur la figure 1 ;
• la figure 3 est une vue à plus grande échelle et en perspective de la partie II de la figure 1 ;
• la figure 4 est une vue semblable à la figure 1 d'un résonateur à cavité coaxiale selon l'invention, pourvu d'une pluralité de dispositifs d'accord,
• la figure 5 est une vue de dessus en direction de la flèche V de la figure 4, et
• la figure 6 est une vue semblable à la figure 3, mais l'élément de commutation étant formé par un transistor.

The invention will be better understood and other objects, characteristics, details and advantages thereof will appear more clearly in the explanatory description which follows, made with reference to the appended schematic drawings given solely by way of example illustrating an embodiment. of the invention and in which:

• Figure 1 is a schematic side view of a coaxial cavity resonator according to the invention;
• Figure 2 is an exploded view of the part indicated by arrow II in Figure 1;
• Figure 3 is an enlarged perspective view of part II of Figure 1;
• FIG. 4 is a view similar to FIG. 1 of a coaxial cavity resonator according to the invention, provided with a plurality of tuning devices,
• FIG. 5 is a top view in the direction of the arrow V in FIG. 4, and
• Figure 6 is a view similar to Figure 3, but the switching element being formed by a transistor.

The figures show, as an example of the setting implementation of the invention, a tunable multicoupler in an octave frequency band, electronically, with short switching times, power for the high frequency domain, up to ultra-high frequencies and microwaves, low intermodulation rate.

This multicoupler essentially comprises a low impedance coaxial cavity resonator 1 of quarter wave type, including the central body 2 which constitutes the line has a cylindrical shape whose face upper 3 serves as a mounting surface for a plurality of tuning devices 5 of which only one is shown in FIG. 1. This device 5 is controlled by a control device 6 partially arranged on the plate upper 8 of the resonator, rectangular, and partly outside. This plate is put at the mass. Reference numbers 10 and 11 denote respectively the profiles forming the walls the resonator and the cover of the bias circuits. Reference numbers 13 and 14 respectively indicate the connectors and the coupling loops to the access connectors 13.

With particular reference to Figures 2 and 3, we will describe below the structure and assembly of a tuning device 5 according to the invention. Such device basically includes a PIN diode high power 16 fixed under the upper plate 8 and a tuning capacity 17 mounted on the upper face 3 of body 2, these two elements being mounted in series by through an elastic washer 18.

More specifically, the housing 19 of the PIN diode 16 is provided with a threaded end piece 20 which passes through the plate 8 and a shoulder 21 which come into application pressed against the underside of the plate 8 under the effect of a tightening nut 22 screwed on the end free from tip 20.

The tuning capacity 17 is a capacity of thick power, with reduced losses, consisting of a plurality of microwave ceramic capacitors 24 paralleled and welded on a common support 25 from which protrudes a nozzle 23 screwable into a orifice 26 in the upper face 3 of the central body 2 of the resonator. The support 25 and the end piece 23 form a shoulder 27 by which the support 25 rests on the upper face 3 of the body 2. Such a constitution of the ability to agree allows him to keep the quality coefficient for each of its capacities elementary, therefore to be able to support powers higher without deteriorating filter performance tunable.

The washer 18 is received in a support of washer 29 of cylindrical shape which rests on the face upper capacity 24. The upper surface of the washer 18 is free to be in electrical contact with the PIN 16 LED.

The tuning device 5 is connected electrically to the diode control device 6 by an electrical contact made in the form of a rod spring 28, which passes through the plate 8 in the engaged state in an insulating spacer 34 and one end of which is connected to a self 30, while the other end 32 is pressed by a spring (not shown) against an annular face 33 of the support washer 29, which surrounds the housing of washer 18.

It should also be noted that the choke 31 is connected to a capacity 35, grounding of the plate 8 at 36 and connected by a conductor 37 to an external part 38 of the control device.

Referring to Figures 4 and 5, we see that the multicoupler arrangement according to the invention comprises a plurality of tuning devices 5, mounted on the circular upper surface 3 of the block forming line 2 of the coaxial resonator. These tuning devices are arranged angularly equidistant on a circle, near the periphery of the body 2. The use of a coaxial cavity provides a surface of mounting of tuning devices, one size relatively large. The number of these devices 5, defined by the desired chord band, the pitch of desired frequency and power handling can thus be larger than necessary. The invention thus allows reduce the voltages across the PIN diodes. In the example shown, 10 diodes are provided while for example only 8 are needed.

It should be noted that the relative positions of the tuning devices are not just any. To to obtain the best performance it is advantageous to arrange the capacitors so that the difference between two successive tuning capacities, the more small possible.

As an example, we will choose the arrangement of the ten capacitors noted a to j in Figure 5 as shown in the table below, the first column indicating the capacitor, the second column the value in [pF] and the third column the binary digit that represents the capacitor. This table shows, as indicated above, that the last two capacitors constitute the ninth binary digit, which improves the power handling of the last chord pitch. TUNING CAPACITOR CAPACITY [pF] BINARY NUMBER at 0.1 1 b 0.2 01 vs 0.4 001 d 0.8 0001 e 1.6 00001 f 3.2 000001 g 6.4 0000001 h 12.8 00000001 i 12.8 000000001 j 12.8 0000000001

Of course multiple modifications can be made to the embodiment of the invention which has just been described. In the example given, the elements switching diodes are PIN diodes. However others semiconductor switching elements can be choose. So the switching element can be consisting of a transistor. Figure 6 shows the assembly of such a transistor. In this figure we use the same references as in FIGS. 1 to 5 for identical or similar components. The element of switching 16 which is now formed by a transistor, has three ohmic contacts which is to connect to voltage sources. Termination dissipating the most energy, namely the collector or drain, is earthed for example by screwing it, or its support on the plate 8, like the end piece 20. The polarization electrode 42, namely the base where the grid, is directly polarized by an element of contact 43 of the same type as contact 28. The third electrode, i.e. the emitter or source 44, which comes out laterally of the transistor housing is connected by a additional element 45 to support 29 of capacity Okay. It will then be polarized as described for the PIN LED.

The choice between a transistor and a PIN diode could be done from the parameters of manufacturing and performance desired for the filtered. Regarding the dimensions of the transistor, these are not a problem since we can adapt the diameter of the core of the coaxial.

The invention as described and shown in the figures provide many advantages. Putting tuning capacitors with improved overvoltage in series with high power PIN diodes, we bring a solution to the main problem of using these diodes, which resides in their loss coefficient too high or their overvoltage too low as well as in their high parasitic capacity due to the housing and limiting the frequency variation achievable by a single diode PINE. The use of a coaxial cavity makes it possible to have a large upper surface allowing the mounting a number of chord elements greater than strictly necessary number. The invention provides the use of thick, lossy power capacities reduced, consisting of for example six capacitors microwave type ceramics, paralleled and welded in a common screwable support. The mounting of tuning devices, with spring contact and washer elastic ensures separation of the dissipating elements energy, each with a different heat sink. The invention thus allows ease of assembly, which tolerates variations in dimensions due to tolerances mechanical and thermal expansions and a maintenance possible diode to diode. There are no more soldering of contact wires on the diodes. The upkeep thus the initial reliability of the diodes is ensured. The assembly according to the invention of the various elements constitutive of the devices of agreement between them and on the upper plate and the central block of the resonator allows easy maintenance and disassembly of devices and a replacement of diodes. On the other hand, thermal contacts between the PIN diode boxes and the ground plate and between the tuning capacities and the central block are excellent. It should also be noted that the invention can preferably be used in a frequency band from a few tens of MHz up to several GHz.

Claims (16)

Filter or multicoupler type arrangement, comprising at least one resonator electronically tunable by a tuning device, which comprises at least one tuning element such as a tuning capacitor, a switching element for connecting the tuning element electronically selectively tuning to said resonator and a device for controlling the switching element, characterized in that the resonator is produced in the form of a coaxial resonator (1) of the quarter wave type, comprising a central member (2) which has a free surface (3) perpendicular to the axis capable of serving as a mounting surface for the tuning devices (5). Arrangement according to claim 1, characterized in that the various components of a tuning device (5), which dissipate energy and have a different heat sink are dismountably mounted. Arrangement according to claim 2, characterized in that the aforementioned elements are maintained in mechanical and electrical contact in the tuning device under the effect of pressure forces, advantageously of spring. Arrangement according to claim 3, characterized in that the switching element (16) and the tuning capacitor (17) are mounted in series between an upper plate (8) of the resonator and the body (2) forming the line, the switching element being removably attached by its housing (19) to said plate (8) and the tuning capacity (17) being removably attached to the body (2) and the two being electrically interconnected in series by an elastic washer (18). Arrangement according to claim 4, characterized in that the housing (19) of the switching element (16) comprises a threaded end piece (20) intended to pass through the upper plate (8) and is provided with a support shoulder (21) against the internal face of the plate under the tightening effect of a nut (22) screwed onto the end piece on the other side of the plate. Arrangement according to one of claims 4 or 5, characterized in that the tuning capacity (17) comprises a support (25) provided with a threaded end piece (23) which can be screwed into the upper face of the body (2) forming the line. Arrangement according to one of claims 4 to 6, characterized in that the switching element (16) rests on a front face of the elastic washer (18) the other face of which is received in a support (29) resting on the capacity to agree (17). Arrangement according to one of claims 4 to 7, characterized in that the tuning capacitor (17) comprises a plurality of power capacitors (24) placed in parallel and welded in the aforementioned screwable support (25). Arrangement according to one of claims 1 to 8, characterized in that the electrical contact between the control device (6) of a switching element (16) and the controlled element (16) is formed by a contact element (29) produced in the form of a spring rod, one end of which is connected to the control device while the other end (32) is pressed under the effect of a spring against the aforementioned washer support (29). Arrangement according to one of Claims 1 to 9, characterized in that the upper mounting surface (3) of the body (2) of the tuning devices (5) is adapted to allow the mounting of a number of tuning devices. agreement (5) greater than that strictly necessary for the realization of the frequency steps. Arrangement according to one of the preceding claims, characterized in that the switching element (16) is a PIN diode. Arrangement according to one of the preceding claims, characterized in that the tuning capacitors are arranged in a zone in the form of a crown on the central member. Arrangement according to claim 12, characterized in that the capacitors are arranged so that the difference between two successive tuning capacitors is as small as possible. Arrangement according to one of the preceding claims, characterized in that the switching element (16) is a transistor. Arrangement according to claim 14, characterized in that the collector or drain of the transistor is earthed, the base or gate could be directly polarized by a contact element and the emitter or the source is brought into contact with the support. ability to agree. Multicoupler assembly, characterized in that it is formed by a combination of several arrangements according to one of the preceding claims.

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