RU166141U1 - SUPER HIGH FREQUENCY FERRITE FILTER - Google Patents

Abstract

1. Microwave ferrite filter containing a non-magnetic casing located in the gap between the upper and lower parts of the electromagnet, at least two spherical single-crystal ferrite resonators (FRs) mounted on heat-conducting cermet rods in the resonator chambers of the non-magnetic casing, in two of which (extreme) through the first channels in a non-magnetic case, respectively, the input and output segments of transmission lines are drawn, the central conductors of which are loaded on short-circuited The final case is single-turn communication elements (WES), FRs are electromagnetically connected to each other by means of double WES, short-circuited to the non-magnetic case at the free ends and connected by conductors of length L <λ / 4, passed through the second channels of the non-magnetic case, where λ is the wavelength in the working range of frequency tuning from f to f single and double wind farms, intersecting in pairs in pairs, cover the FR, while the intersection points of single and double wind farms are removed from the FR by a distance relative to the longitudinal symmetry axes of the resonator Amer equal 0.25-1.0 the diameter DF d, and the diameter d≤0,30-0,50 mm.2. The filter according to claim 1, characterized in that the spherical single-crystal FRs are removed from the longitudinal symmetry axes of the resonator chambers, and the intersection points of single and double wind farms are located on the longitudinal symmetry axes of the resonator chambers. 3. The filter according to claim 1, characterized in that the centers of the spherical single-crystal FRs are located on the longitudinal symmetry axes of the resonator chambers, and the intersection points of the wind farms are removed from the longitudinal symmetry axes of the resonator chambers by tilting the wind turbine planes at an angle of 5-30 °

Description

The utility model relates to radio electronics and microwave technology, namely, to electrically frequency-tunable filters containing miniature ferrite single-crystal spherical samples magnetized by an electromagnet surrounded by coil communication elements (WES) as resonators.

In electrically tunable filters on ferrite resonators (FR), the commonly required width Δf ₃ of the passband at the level of minus 3 dB lies, depending on the given wavelength range, in the following ranges: 10-20 MHz in the meter range, 15-30 MHz in the decimeter range, 25-50 MHz in the centimeter range, 50-400 MHz - in the millimeter range. In this case, the minimum losses α _min in the passband during octave tuning of the resonant frequency of the filter, depending on the number of FRs, do not exceed: 2.5 dB for two-link (two-cavity) filters, 3-4 dB for four-link filters, 5-6 dB for six-link filters filters. Filters based on ferrite resonators with a wide passband of 250-500 MHz are also known. The creation of frequency synthesizers for transmitting devices required the development of microwave filters with extremely narrow passband. The bandwidth of a single-link ferrite filter on orthogonal orbit communication elements (WES) is determined by the expression:

γ = 2.8 MHz / Oe,

ΔH is the line width of the ferromagnetic resonance, Oe;

k is the coupling coefficient of the RF with orthogonal wind farms;

In this case, the coupling coefficient is determined as follows:

4пM _s is the saturation magnetization of a single crystal of FR, G;

ω = 2пf - signal frequency, MHz;

r is the radius of the FR, cm;

R is the radius of the wind farm, cm;

φ is the angle of the WES ferrite resonator, radian.

Expressions (1), (2) show that in order to reduce the filter passband, it is necessary to reduce the coupling coefficient of the FR with the wind farm and the intrinsic width of the FMR line (ΔH), namely: reduce 4пM _s, decrease the radius of the FR, increase the radius of the wind farm. However, reducing the bandwidth of a single-link filter leads to an increase in resonant (minimum) losses in the passband, which is an undesirable fact. Similar patterns also occur in a multi-link filter, that is, containing several interconnected RFs.

Known microwave ferrite filter (see patent RU 154064, IPC H01P 1/218, published 10.08.2015), containing a non-magnetic housing located in the gap of the electromagnet, at least two spherical single-crystal ferrite resonators mounted on heat-conducting ceramic rods in non-magnetic resonance chambers cases, in two of which through the first channels in the non-magnetic case the input and output sections of the transmission line are respectively conducted, the central conductors of which are loaded onto the short-circuited ones of the non-magnetic case spherical coil communication elements, spherical single-crystal ferrite resonators are electromagnetically connected to each other by means of double coil communication elements, short-circuited to the non-magnetic housing at the free ends and connected by conductors passed through the second channels of the non-magnetic housing, single and double coil communication elements pairwise orthogonally enclose spherical single-crystal ferrite resonators, conductors in the second channels of the non-magnetic case are enclosed in the introduced dielectric volts LCI made of silicone sealant to the permittivity ε _r is not more than 2.5 and the dielectric loss tangent of tgδ not more than 0.01, the width b _in mm, the height h _in mm, the length L _in mm, dielectric sleeve and the radius R _B , mm, of its internal channel are selected from certain ratios.

A disadvantage of the known microwave ferrite filter is the impossibility of achieving an extremely narrow passband with minimal (resonant) losses.

A known microwave ferrite filter (see patent RU 157816, IPC H01P 1/218, published December 10, 2015), comprising a non-magnetic housing with resonant chambers located together with shielding chambers with non-magnetic metal spacers in the gap between the pole tips of the electromagnet, spherical single-crystal ferrite resonators, oriented in the isotropic direction on the heat-conducting cermet rods in the resonance chambers of the non-magnetic body, in the extreme of which through the first channels in the non-magnetic body respectively, the input and output segments of the transmission line, the central conductors of which are loaded on single-wound single-wound coupling elements, covering extreme ferrite resonators, spherical single-crystal ferrite resonators are electromagnetically connected to each other by means of double-wound coupling elements, short-circuited on the non-magnetic case at the free ends and connected by conductors of length L <λ / 4, passed through the second channels of the non-magnetic case, where λ is the wavelength than the filter tuning range, single and double coil communication elements pairwise orthogonally cover spherical single-crystal ferrite resonators, while across from at least one spherical single-crystal ferrite resonator having a reduced resonant frequency, a through hole is made in at least one non-magnetic metal shielding gasket in which is placed flush with a disk of soft magnetic material adjacent to one of the pole tips of an electromagnet .

A disadvantage of the known microwave ferrite filter is not a sufficiently narrow passband with minimal (resonant) losses.

A known microwave ferrite filter (see patent RU 148202, IPC H01P 1/20, published November 27, 2014), which coincides with this decision by the largest number of essential features and adopted as a prototype. The known microwave ferrite filter prototype contains a non-magnetic casing located in the gap of the electromagnet, at least two spherical single-crystal FRs mounted on heat-conducting cermet rods in the resonator chambers of the non-magnetic casing. Into the extreme resonator chambers, through the first channels in a non-magnetic case, the input and output segments of the transmission line are respectively drawn. The central conductors of the input and output segments of the transmission line are loaded on single-loop single-turn communication elements (WES) short-circuited on a non-magnetic housing, covering the extreme FR. Ferrite resonators are electromagnetically coupled to each other using double wind farms, short-circuited to the non-magnetic case at the free ends and connected by conductors of length L <λ / 4, passed through the second channels of the non-magnetic case, where λ is the wavelength in the working frequency tuning range from f _min to f _max microwave ferrite filter. Single and double wind farms pairwise orthogonally cover the DF.

In the known filter to reduce losses in the passband when operating in wide frequency ranges (octave or more) between the opposite ends of the upper and lower parts of the electromagnet there is a metal gasket 10-150 μm thick between the extreme FR having a higher resonant frequency and its corresponding segment transmission lines. This ensures equalization of the resonant frequencies of the extreme FRs when they are oriented in the isotropic direction to ensure thermal stability and wide range.

A disadvantage of the known microwave ferrite filter is the inability to achieve an extremely narrow passband with acceptable minimum (resonant) losses.

The objective of this utility model is to develop such a microwave ferrite filter that would provide narrower bandwidths Δf ₃ with acceptable (fairly small) minimum losses in the passband (α _min ≤54 ÷ 10 dB).

The problem is solved in that the microwave ferrite filter contains a non-magnetic casing located in the gap of the electromagnet, at least two spherical single-crystal FRs mounted on heat-conducting cermet rods in the resonator chambers of the non-magnetic casing, in two of which (extreme) through the first channels in the non-magnetic casing respectively, the input and output segments of the transmission line are carried out, the central conductors of which are loaded on a single wind farm, FR electromagnetically shorted to a non-magnetic case are coupled with each other by means of double wind farms short-circuited to the non-magnetic case at the free ends and connected by conductors L <λ / 4, passed through the second channels of the non-magnetic case, where λ is the wavelength in the working range of the filter frequency tuning from f _min to f _max , single and double wind farms, intersecting in pairs, cover the FR, being close to the FR. New is that the intersection points of single and double wind farms are removed from the FR by a distance relative to the longitudinal symmetry axes of the resonator chambers, equal to 0.25-1.0 of the diameter d of the FR, while the diameter d≤0.30-0.50 mm.

The choice of the interval for removing the wind farm from the FR due to the fact that at a distance of less than 0.25 of the diameter of the FR there is no significant narrowing of the passband, and at a distance of more than 1.0 diameter of the FR, the losses in the passband of the microwave ferrite filter increase sharply.

If necessary, between the opposite ends of the upper and lower parts of the electromagnet there is a metal gasket 10-150 μm thick located between the extreme spherical single-crystal ferrite resonator having a higher resonant frequency and the corresponding segment of transmission lines.

Two versions of the proposed microwave ferrite filter are possible.

In one embodiment, the FRs are removed from the longitudinal symmetry axes of the resonator chambers by shortening or lengthening the heat-conducting cermet holders, and the intersection points of the wind farms are aligned with the longitudinal symmetry axes of the resonator chambers.

In another embodiment, the intersection points of the wind farms are shifted to one or the other side relative to the FR by a slight tilt (inclination angle of not more than 5-30 degrees) of the wind farm planes to the longitudinal symmetry axes of the resonator chambers, and the centers of the FR are located on the longitudinal symmetry axes of the resonator chambers.

The present utility model is illustrated in the drawing, where:

in FIG. 1 shows a real microwave ferrite filter, shown for clarity, without the upper part of the electromagnet and without a disk shielding the resonator chambers (the FRs are offset from the longitudinal symmetry axes of the resonator chambers);

in FIG. 2 shows a side view of a real microwave ferrite filter with a section of the electromagnet along the longitudinal axis (the longitudinal axes of the resonator chambers are shown by thin lines);

in FIG. 3 is a close-up top view of the chambers of a real microwave ferrite filter with a first arrangement of the RF and wind farm in them;

in FIG. Figure 4 is a close-up top view of the chambers of a real microwave ferrite filter with a second arrangement of the RF and wind farm in them;

in FIG. 5 shows a close-up top view of the chambers of a real microwave ferrite filter with a third arrangement of the RF and wind farm in them;

in FIG. Figure 6 is a close-up top view of the chambers of a real microwave ferrite filter with a fourth arrangement of the RF and wind farm in them;

in FIG. 7 in the table shows the test results of a microwave ferrite two-cavity filter in the frequency range 13-15 GHz.

Depicted in FIG. 1, FIG. 2, this microwave ferrite filter contains a non-magnetic housing 1, located in the gap 2 between the upper part 3 and the lower part 4 of the electromagnet 5, at least two FR 6 (the figure shows 3 FR 6), mounted on heat-conducting cermet rods 7 in the resonator chambers 8, 9, 10 of the non-magnetic housing 1. Into the two outermost resonator chambers 8, 9 through the first channels 11, 12 in the non-magnetic housing 1, respectively, the input and output segments of the transmission line are drawn, the central conductors 13, 14 of which are loaded on short-circuited on the non-magnet single housing 1 single wind farm 15, 16, surrounding the extreme FR 6. Ferrite resonators 6 are connected to each other using double wind farm 17, 18, 19, short-circuited to non-magnetic housing 1 at the free ends and connected through the second channels 20, 21 of the non-magnetic housing 1 by conductors 22, 23 of length L <λ / 4, where λ is the wavelength in the working range of tuning the microwave ferrite filter. Single WES 15, 16 and double WES 17, 18, 19 intersect in pairs and are close to spherical single-crystal FR 6 in each of the resonator chambers 8, 9, 10. The extreme spherical single-crystal FR 6 with the help of heat-conducting cermet rods 7 are oriented in the magnetizing field H of electromagnet 5 along the isotropic direction (along the “thermal axis”) in order to ensure the stability of the resonant frequency and parameters of the microwave ferrite filter in a wide range of frequencies and temperatures. In this case, the ceramic-metal rods 7 are passed through radiators 24, on which thermistors 25 are mounted, connected to a voltage source of 26 ± 3 V. The resonant frequencies f _{i of the} extreme spherical single-crystal FR 6 are determined by the formula:

γ is the gyromagnetic ratio of 2.8 MHz / Oe;

H _a - the anisotropy field of a spherical single-crystal FR in the isotropic direction is zero, Oe;

f _swi is the coupling frequency, inversely proportional to the loaded Q factor of the resonator Q _Hi , MHz;

H _i - the magnetic field in the working gap 2 of the electromagnet 5 in the area of each i-th FR 6 (i = l, 2, 3), E.

Intermediate RF 6s in a multi-link microwave ferrite filter placed on the same cermet rods 7 serve to match their resonant frequencies with the frequencies of the extreme RF 6s to form a qualitative amplitude-frequency characteristic of the microwave ferrite filter. An electromagnet 5, consisting, as a rule, of two parts 3, 4 (see Fig. 2), in which control coils 27 can be fixed on the pole pieces 26. Between the pole pieces 3, 4 of the electromagnet 5 in the gap 2, in addition to the non-magnetic case 1 with FR 6, there are also disks 28 made of non-magnetic foil with a thickness of t = 20-60 μm to ensure the electro-tightness of the resonator chambers 8, 9, 10, which provides a high microwave barrier out-of-band ferrite filter. The input and output segments of the transmission lines exit the electromagnet 5 in the form of, for example, microwave coaxial connectors 29, 30 (or microstrip connectors). Between the ends of the upper 3 and lower 4 parts of the electromagnet 5 can be installed metal gaskets 31 with a thickness of 10-150 μm, aligning the resonant frequencies of the extreme FR 6 oriented in the isotropic direction (along the "thermal axis") in order to ensure thermal stability. In this microwave ferrite filter, the points of intersection of the wind turbines and the centers of the FR 6 are spaced from each other relative to the longitudinal symmetry axes of the resonator chambers 8, 9, 10. At the same time, the extreme (single) wind turbines 15, 16 are 0.25-1 removed from the extreme FR 6 , 0 of diameter dF, diameter d≤0.30-0.50 mm., Providing the required narrow passband, middle (double) wind farms 17, 18, 19 are removed from FR 6 by a distance of 0.25-1.0 diameter d FR, diameter d≤0.30-0.50 mm., At which a subcritical connection between them is ensured (there is no bifurcation of the resonance curve) when reaching the same time enno least minimum loss of the signal transmission therebetween. In this case, the parameters of spherical single-crystal FRs are selected from the conditions:

saturation magnetization 4pM _s ≤f _min 3 / 2γ, unit; which causes the operation of the microwave ferrite filter with input maximum powers of more than 10 mW;

ferromagnetic resonance line width ΔH≤0.2-0.57, E.

Several embodiments of the present microwave ferrite filter are possible, which are illustrated in FIG. 3-fig. 6.

In the first embodiment (see Fig. 3, Fig. 4), spherical FR 6 mounted on heat-conducting cermet rods 7 in the resonator chambers 8, 9, 10 are removed from the longitudinal axis of symmetry of the resonator chambers by shortening (see Fig. 3 ) or lengthening (see Fig. 4) of the heat-conducting rods 7. At the same time, the intersection points of the single wind farm 15, 16 and double wind farm 17, 18, 19 are aligned with the longitudinal axis of symmetry of the resonator chambers 8, 9, 10.

In the second embodiment (see Fig. 5, Fig. 6), the intersection points of the wind farm 15-19 are shifted to one or the other side relative to the ferrite resonators by a slight tilt (inclination angle of 5-30 degrees) of the wind farm 15-19 planes relative to the direction of the magnetizing field H of the electromagnet 5, while the centers of the DF are located on the longitudinal axis of symmetry of the resonator chambers 8, 9, 10. By the way, the direction of the magnetizing field H of the electromagnet 5 always coincides with the direction of the longitudinal axis of symmetry of the resonator chambers 8, 9, 10.

In the process of developing this microwave ferrite filter, tests were carried out of the RF located in the center (along the longitudinal axis) of the resonator chambers made of different grades of single crystals and with different distances from the wind farms from the RF and different inclination of the wind farms relative to the field H of the electromagnet. In FIG. 7 in the table shows the test results of a microwave ferrite two-cavity filter in the frequency range 13-15 GHz. The table shows that in the case of choosing a 140 KG single crystal having 4пM _s closest to the inequality 4пM _s ≤f _min 3 / 2γ, as well as the minimum diameter and ΔH, the microwave ferrite filter has the most narrow passband Δf ₃ = 8 MHz at minimum loss in the passband α _min = 3.5 dB. In this case, the angle of inclination of the wind farm to the direction of the field H is ≈25 degrees. Temperature tests of a ferrite filter containing 140 KG FR when tuned to a minimum bandwidth Δf ₃ = 8 MHz with a minimum loss of 3.5 dB are given below:

T = 20 ° C, Δf ₃ = 8 MHz, α _min = 3.5 dB, Δα = 0 dB;

T = 70 ° C, Δf ₃ = 8.5 MHz, α _min = 5, l dB, Δα = 0 dB;

T = -60 ° C, Δf ₃ = 11 MHz, α _min = 4.5 dB, Δα = 0 dB.

The departure of the resonant frequency did not exceed ± 3 MHz - the filter parameters remained practically unchanged when the filter frequency was tuned within 13-15 GHz.

Claims (4)

1. Microwave ferrite filter containing a non-magnetic casing located in the gap between the upper and lower parts of the electromagnet, at least two spherical single-crystal ferrite resonators (FRs) mounted on heat-conducting cermet rods in the resonator chambers of the non-magnetic casing, in two of which (extreme) through the first channels in a non-magnetic case, respectively, the input and output segments of transmission lines are drawn, the central conductors of which are loaded on short-circuited The final housing is single-turn communication elements (WES), FRs are electromagnetically connected to each other by means of double WES, short-circuited to the non-magnetic case at the free ends and connected by conductors of length L <λ / 4, passed through the second channels of the non-magnetic case, where λ is the wavelength in the operating range of frequencies from f _min to f _{max adjustment,} single and double WEC, intersecting each other pairwise cover DF, wherein the point of intersection of single and double VES removed from RF to a distance relative to the longitudinal axes of symmetry of resonator molecular chambers equal 0.25-1.0 the diameter d FR and d≤0,30-0,50 mm diameter. 2. The filter according to claim 1, characterized in that the spherical single-crystal FRs are removed from the longitudinal symmetry axes of the resonator chambers, and the intersection points of single and double wind farms are located on the longitudinal symmetry axes of the resonator chambers. 3. The filter according to claim 1, characterized in that the centers of the spherical single-crystal FRs are located on the longitudinal symmetry axes of the resonator chambers, and the intersection points of the wind farms are removed from the longitudinal symmetry axes of the resonator chambers by tilting the wind turbine planes at an angle of 5-30 ° relative to the direction of the magnetizing field of the electromagnet . 4. The filter according to claim 1, characterized in that between the opposite ends of the upper and lower parts of the electromagnet there is a metal gasket 10-150 μm thick located between the extreme spherical single-crystal ferrite resonator having a higher resonant frequency and the corresponding segment of transmission lines.

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