# Patent

## Title
Enhanced Q high dielectric constant material for microwave applications

## Abstract

Enhanced Q high dielectric constant material for microwave applications. In some embodiments, a composition can include a material with a formula Ba4+xSm(2/3)(14−x+0.5y)Ti18−yAlyO54, with the quantity y being in a range 0<y<2, and the quantity x being in a range 0<x<2−y. Such a material can have a dielectric constant value greater than 60 and a Qf value greater than 10,000 at a frequency (f) at or less than 1 GHz. In some embodiments, a material having such properties can be implemented as a ceramic device and be utilized as a dielectric microwave resonator. Such a microwave resonator can be utilized as, for example, a narrowband radio-frequency (RF) filter.

## Background
CROSS-REFERENCE TO RELATED APPLICATION(S)
This application claims priority to U.S. Provisional Application No. 61/912,463 filed Dec. 5, 2013, entitled ENHANCED Q HIGH DIELECTRIC CONSTANT MATERIAL FOR MICROWAVE APPLICATIONS, the disclosure of which is hereby expressly incorporated by reference herein in its entirety.


BACKGROUND
Field
The present disclosure generally relates to high dielectric constant materials for microwave applications.
Description of the Related Art
In some radio-frequency (RF) applications such as microwave applications, ceramic materials are often utilized as, for example, dielectric resonators. Such dielectric resonators can be implemented in devices such as narrowband filters.
SUMMARY OF THE INVENTION
In some implementations, the present disclosure relates to a composition including a material with a formula Ba4+xSm(2/3)(14−x+0.5y)Ti18−yAlyO54, with the quantity y being in a range 0<y<2, and the quantity x being in a range 0<x<2−y.
In some embodiments, the quantity x can be in a range 0<x<1−0.5y corresponding to barium content being in a range of 0% to 50%. In some embodiments, the quantity y can be approximately 0.5 and the quantity x can be in a range from approximately 0.01 to approximately 1.0. In some embodiments, the quantity y can be approximately 1.0 and the quantity x can be in a range from approximately 0.01 to approximately 0.5. In some embodiments, the quantity y can be approximately 1.4 and the quantity x can be in a range from approximately 0.01 to approximately 0.3.
In some embodiments, at least some of Sm can be substituted by another lanthanide including La, Ce, Pr, Nd or Gd. In some embodiments, the other lanthanide such as La or Nd can substitute up to approximately 50 atomic percent of Sm.
In some embodiments, at least some of Ba can be substituted by Sr. Sr can substitute up to approximately 30 atomic percent of Ba.
In some embodiments, the composition can further include a minor additive including manganese oxide, manganese carbonate, cerium oxide, copper oxide, germanium oxide, silica or gallium oxide. The minor additive can constitute less than approximately 2 percent by weight. The minor additive can be cerium oxide or manganese oxide; and such a minor additive can constitutes less than 0.5 percent by weight.
In some embodiments, a composition having one or more of the foregoing features can further include a high Q second phase material. The high Q second phase material can include TiO2, BaTi4O9 or Ba2Ti9O20.
According to a number of implementations, the present disclosure relates to a dielectric resonator having a ceramic device configured as a microwave resonator. The ceramic device includes a material with a formula Ba4+xSm(2/3)(14−x+0.5y)Ti18−yAlyO54, with the quantity y being in a range 0<y<2, and the quantity x being in a range 0<x<2−y.
In some embodiments, the material can have a dielectric constant value that is greater than 60 for frequencies less than or equal to 1 GHz. Such a dielectric constant value can be in a frequency range that is greater than or equal to 700 MHz and less than or equal to 1 GHz. In some embodiments, the material can have a Qf value that is greater than 10,000, with the quantity Q being a quality factor, and the quantity f being a frequency expressed in GHz.
In accordance with some teachings, the present disclosure relates to a narrowband radio-frequency (RF) filter having an input port and an output port, and one or more dielectric resonators implemented between the input port and the output port. Each of the one or more dielectric resonators includes a ceramic device. The ceramic device includes a material with a formula Ba4+xSm(2/3)(14−x+0.5y)Ti18−yAlyO54, with the quantity y being in a range 0<y<2, and the quantity x being in a range 0<x<2−y.
In a number of implementations, the present disclosure relates to a method for fabricating a tungsten bronze material having titanium (Ti) in a plurality of octahedral sites. The method includes substituting aluminum (Al) for at least some of the titanium (Ti) in the octahedral sites to yield a dielectric constant value greater than 60 and a Qf value greater than 10,000 at a frequency (f) at or less than 1 GHz. The method further includes adjusting contents of rhombic (A1) sites and pentagonal (A2) sites to compensate for charge imbalance resulting from the aluminum substitution of titanium.
In some embodiments, the tungsten bronze material can be represented by a formula [A2]4[A1]10Ti18−yAlyO54. In some embodiments, substantially all of the pentagonal A2 sites can be occupied by barium (Ba) and at least some of the rhombic A1 sites can be occupied by samarium (Sm), such that the adjusting includes adding x formula unit of Ba and (2⁄3)x formula unit of Sm to the rhombic A1 sites. In some embodiments, the method can further include substituting at least some of the samarium with another lanthanide (Ln) to yield a temperature coefficient of resonant frequency (v) that is less negative.
For purposes of summarizing the disclosure, certain aspects, advantages and novel features of the inventions have been described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment of the invention. Thus, the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows that in some embodiments, a ceramic device such as a puck can include a material having one or more features as described herein.
FIG. 2 shows that in some embodiments, a ceramic puck having one or more features as described herein can include a center aperture dimensioned to allow, for example, tuning of the ceramic puck when utilized as a microwave resonator.
FIG. 3 shows an example of a tunable microwave resonator configuration.
FIG. 4 shows an example of a cavity filter having a plurality of cavities arranged between radio-frequency (RF) ports.
FIG. 5 shows an example of an RF system that can utilize one or more of the filter device of FIG. 4.
FIG. 6 shows a process that can be implemented to fabricate a ceramic material having one or more features as described herein.
FIG. 7 shows a process that can be implemented to press-form a shaped object from a powder material prepared as described herein.
FIG. 8 shows example stages associated with the process of FIG. 7.
FIG. 9 shows a process that can be implemented to sinter formed objects having one or more features as described herein.
FIG. 10 shows example stages associated with the process of FIG. 9.



DETAILED DESCRIPTION OF SOME EMBODIMENTS
The headings provided herein, if any, are for convenience only and do not necessarily affect the scope or meaning of the claimed invention.
Disclosed are compositions that can include materials having relatively high dielectric constant values and enhanced Q values. Examples of such materials are described herein in greater detail. Also described herein are examples of how such materials can be manufactured. Also described herein are examples of devices and applications in which such materials can be utilized.
In some radio-frequency (RF) applications such as microwave applications (e.g., low-frequency (700 MHz-1 GHz) applications), materials with a dielectric constant greater than 60 and having a desired or optimized quality factor Q can be desirable. For example, a Qf (product of Q and frequency f) value greater than 10,000 in the foregoing frequency range (700 MHz to 1 GHz range) can be desirable. Further, such a material preferably has a temperature coefficient of resonant frequency that is near zero. Conventional high-dielectric-constant materials typically do not have sufficient Q and/or require expensive raw materials such as gallium (Ga) or germanium (Ge).
Disclosed are various examples of materials that can meet desired Q specifications or requirements without the expensive raw materials in their respective compositions. Also disclosed are examples of how such materials can be implemented in low-frequency microwave applications. Although described in such low-frequency context, it will be understood that one or more features of the present disclosure can also be implemented in other RF applications.
Various examples of dielectric materials and associated methods are described in U.S. Pat. No. 8,318,623 which is expressly incorporated by reference in its entirely and to be considered part of the specification of the present application.
Some compounds with an orthorhombic tungsten bronze structure can be represented by a general formula

Ba6−3xLn8+2xTi18O54,  (1)

where Ln can be a lanthanide such as lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm) or gadolinium (Gd). Such a structure can be implemented for microwave dielectric applications due to their high dielectric constants (e.g., 60-100) and their ability to be tuned to a near zero temperature coefficient of resonant frequency.

In some applications, it is additionally desirable to minimize or reduce the dielectric loss tangent (tan δ) or to maximize or increase the quality factor Q (an inverse of dielectric loss tangent, 1/tan δ) of a dielectric material used for microwave applications, since such a property typically yields sharper resonances and sharper transitions for filter applications.
From a crystallographic perspective, the foregoing materials can be represented as

[A2]4[A1]10Ti18O54.  (2)

Typically, the 10 available A1 sites are rhombic while the 4 available A2 sites are pentagonal. The Ti atoms typically occupy octahedral sites. The rhombic A1 sites may be occupied by Ba atoms, Ln atoms, or may be vacant. The pentagonal A2 sites may be occupied by Ba or Ln atoms. Although described in the context of rhombic sites, it will be understood that one or more features of the present disclosure can also be implemented in other types of sites.

For the orthorhombic tungsten bronze structure represented by Formula 1, it is generally understood that the value of Q can be optimal when the quantity x has a value of 2⁄3 (0.667), where substantially all of the Ba atoms reside in the pentagonal A2 sites and substantially all of the lanthanide (Ln) atoms reside in the rhombic A1 sites. A number of studies have shown that the value of Q is typically maximum when the lanthanide (Ln) chosen is Sm, and decreases with increasing lanthanide size in the order of, for example, Nd, Pr, Ce and La. The Gd material shows a very limited solid solution range and typically yields a relatively low Q as well.
Among the foregoing lanthanide examples, Sm and Gd are lanthanides that yield negative temperature coefficient of resonant frequency (τf) values. The other lanthanides Nd, Pr, Ce and La series all yield positive τf values. In the context of dielectric resonators, temperature coefficient of resonant frequency (τf) is typically a combination of temperature coefficient of dielectric constant of a resonator, temperature coefficient of the resonator cavity, and the coefficient of thermal expansion of the resonator.
Based on the foregoing properties of the example lanthanides, a typical design strategy can involve blends of two lanthanides such as Sm and Nd or Sm and La to achieve temperature compensated ceramic bodies. Aside from such design considerations based on physical properties, availability and/or cost of raw materials can also impact designs of ceramic devices. For example, there is a demand for ceramic solutions for microwave materials that do not contain scarce and/or costly elements such as neodymium (Nd), gallium (Ga) or germanium (Ge). Samarium (Sm) and lanthanum (La) are significantly less scarce for rare earth elements.
As described in U.S. Pat. No. 8,318,623, as well as in, for example, U.S. Pat. Nos. 5,182,240, 5,185,304 and 5,310,710, at least some of the titanium in tungsten bronze material can be substituted by, for example, aluminum. The resulting charge imbalance can be compensated by adding Ln material (e.g., Nd, a mixture of Nd and Sm, a mixture of Nd and Y, or a mixture of Sm and non-lanthanide Bi) into the vacant rhombic A1 lattice site(s) (e.g., in Formula 2). It is also noted that in the tungsten bronze material of Formula 1 (Ba6−3xLn8+2xTi18O54), for x values less than or equal to 2⁄3 where Ln=Nd (in the BaO—Nd2O3—TiO2 ternary system), the resulting phase is chemically compatible with the high Q rutile form of TiO2 (with τf being greater than approximately 500 ppm/° C.).
In some embodiments, aluminum (Al) can be substituted for titanium (Ti) in the octahedral site to yield, contrary to published findings, highest or enhanced Q material at approximately 1 GHz for x values less than or equal to 2⁄3. In the context of Formula 2, the foregoing substitution of Ti by Al can be represented as

[A2]4[A1]10Ti18−yAlyO54,  (3)

where y unit of Ti is substituted by y unit of Al.

As described herein, charge imbalance resulting from substitution of Ti+4 with Al+3 can be compensated by appropriate occupations of the rhombic A1 and/or pentagonal A2 sites by, for example, Ln+3 and/or Ba+2, respectively. In the context of such Ln and Ba, Formula 3 can be expressed as a modified form of Formula 1, as one of the following example formulas

Ba6−3xLn8+2x+(y/3)Ti18−yAlyO54,  (4A)

Ba6−3x+(y/2)Ln8+2xTi18−yAlyO54, and  (4B)

Ba6−3x−yLn8+2x+yTi18−yAlyO54,  (4C)

where the charge imbalance of y (+4 of Ti to +3 of Al) can be compensated by adding an appropriate amount of Ba (+2), Ln (+3), or a mixture of the two. For example, in Formula 4A, charge balancing can be achieved by adding Ln3+, with the formula unit of y/3 to account for the +3 charge. In Formula 4B, charge balancing can be achieved by adding Ba2+, with the formula unit of y/2 to account for the +2 charge. In Formula 4C, charge balancing can be achieved by subtracting y formula unit of Ba (+2) and adding y formula unit of Ln (+3). It is noted that Formulas 4A and 4B are extreme cases involving only one type of addition (of Ln or Ba), and that the charge imbalance may also be compensated with a mixture of Ln3+ and Ba2+ (such as the example of Formula 4C). Previous studies have taught that the Q is optimal only if all of the barium remains on the pentagonal A2 site and the lanthanide remains on the rhombic A1 site. However, the present disclosure shows that such is not necessarily true.

It is noted that in Formula 4, there are 10 available rhombic A1 sites. Accordingly, and in the context of the example of Formula 4A, a limit can be imposed, where formula unit of 8+2x+(y/3) has a maximum value of 10. In such a configuration, the maximum value for y is 2 when x=2⁄3. In terms of Al substitution of Ti, the maximum amount of aluminum which may be substituted for titanium is 2 formula units (y=2).
Based on the foregoing limit of 2 formula units of aluminum substitution of titanium, aluminum content can be expressed as

aluminum percent=100(y/2),  (5)

where y represents the formula units of aluminum in the composition of Formula 4A. For example, when y=2 in which Formula 4A becomes Ba4Ln10Ti16Al2O54 (with x=2⁄3), aluminum percent is 100%. In another example, when y=1 and x has a value of 2⁄3 based on the formula units for barium (6−3x) being equal to 4, Formula 4A becomes Ba4Ln9.667Ti17AlO54, with aluminum percent being 50%. Note that in both cases (of aluminum percent of 100% and 50%), all of the charge compensation for the aluminum substitution comes from adding additional Ln3+ to the rhombic A1 site.

In some embodiments, where the compensation of the aluminum substitution at least partially occurs by adding Ba2+ to the rhombic A1 site, the maximum amount of barium which can fit into the rhombic A1 site can depend on the foregoing aluminum percent, due to charge balance considerations. The maximum amount of barium which can be placed in the rhombic A1 site (Bamax) is equal to 2-(aluminum percent)/50. The barium percent (in the rhombic A1 site) can then be expressed as (NBa−4)/Bamax, where NBa is the total number of formula units of Ba. Equivalently, barium percent can be expressed as

barium percent=(NBa−4)/(2−(aluminum percent)/50),  (6)

where NBa is the number of barium atoms in the formula (e.g., 6−3x−y in Formula 4). For example, in the case of aluminum percent being 100 (yielding a zero denominator), barium percent is zero, with no barium in the rhombic A1 sites and all of the Ba atoms occupying the pentagonal A2 sites. In another example, the 50%-aluminum configuration that yields the example formula Ba4Ln9.667Ti17AlO54 also results in barium percent of zero, since all of the available aluminum is compensated by additional Ln3+ in the rhombic A1 site. Examples of non-zero barium percent configurations are described herein in greater detail.

As described herein in reference to the example of Formula 4C, an aluminum substitution of titanium by an amount of y formula units can be charge-compensated by an addition of lanthanide (by y formula units) and a subtraction of barium (by y formula units). In the context of zero barium percent configurations, a 100%-aluminum configuration can yield Ba4Ln10Ti16Al2O54, and a 50%-aluminum configuration can yield Ba4Ln9.667Ti17AlO54. In the context of non-zero barium percent configurations, at least some of the barium can occupy the rhombic A1 sites.
In configurations where more than four formula units of barium are present, Formula 4C can be expressed as

Ba4+x′Ln8+2x+y−(2/3)x′Ti18−yAlyO54,  (7)

where x′ represents the additional formula units of barium. Equivalently, x′ can be expressed as x′=NBa−4. Such an increase in Ba (+2) can be charge balanced by a decrease of (2⁄3)x′ formula units of Ln(+3). In Formula 7, the aluminum substitution formula unit quantity y can be greater than zero and less than or equal to 2 as described herein, such that 0<y≦2. The extra-barium formula unit x′ can be greater than or equal to zero, and less than or equal to a maximum value of 2−y, such that 0≦x′≦2−y. Such a maximum value of 2−y can be calculated by, for example, assuming that the Ln formula unit of 8+2x+y−(2⁄3)x′ (of Formula 7) and the additional Ba formula unit of x′ sum to the maximum rhombic A1 site occupation number of 10 (e.g., 8+2x+y−(2⁄3)x′+x′=10). The quantity x′ can be solved to yield x′=2−y.

In some embodiments, all four pentagonal A2 sites can be occupied by barium and the additional x′ formula units of barium can occupy rhombic A1 sites. In such embodiments, since all four of the pentagonal A2 sites are occupied by 6−3x−y formula units (barium number in Formula 4C), 6−3x−y can be set to equal 4, which yields an expression x=(2⁄3)−(1⁄3)y. Substituting such an expression of x into the subscript of Ln in Formula 7, the subscript becomes 8+2[(2⁄3)−(1⁄3)y]+y−(2⁄3)x′, which in turn can be expressed as (2⁄3)[14+(1⁄2)y−x′]. Accordingly, Formula 7 can be expressed as

Ba4+x′Ln(2/3)[14+0.5y−x′]Ti18−yAlyO54,  (8)

where the aluminum substitution formula unit quantity y can be greater than zero and less than or equal to 2, such that 0<y≦2. The extra-barium formula unit x′ can be greater than or equal to zero, and less than or equal to a maximum value of 1−0.5x, such that 0≦x′≦1−0.5y. Such a maximum value of 1−0.5y can be calculated by, for example, assuming that the Ln formula unit of (2⁄3)[14+0.5y−x′] (of Formula 8) and the additional Ba formula unit of x′ sum to the maximum rhombic A1 site occupation number of 10 (e.g., (2⁄3)[14+0.5y−x′]+x′=10). The quantity x′ can be solved to yield x′=1−0.5y. It is noted that in Formula 8, the four formula units of Ba occupy all of the four pentagonal A2 sites; and such occupation is reflected in the Ln formula unit of (2⁄3)[14+0.5y−x′].

In embodiments where lanthanide is samarium (Ln=Sm), Formula 8 can be expressed as

Ba4+x′Sm(2/3)[14+0.5y−x′]Ti18−yAlyO54.  (9)

In such a system, the substitution of aluminum (Al) for titanium (Ti) as described herein can yield high Q rutile form of TiO2 being chemically compatible with Formula 1 (Ba6−3xLn8+3xTi18O54) when the value of x is less than or equal to 2⁄3, similar to the foregoing neodymium (Nd) system (Ln=Nd). In some embodiments of the Sm system, one or more lanthanides having positive τf values can be introduced to compensate for the negative τf value associated with Sm. For example, some of Sm can be substituted by another lanthanide such as La, Ce, Pr, Nd or Gd. In some embodiments, the other lanthanide can be La or Nd, and such lanthanide can substitute up to approximately 50 percent (e.g., mole %) of Sm.

Although various examples are described in the context of barium, it will be understood that one or more of other alkaline earth metals can replace at least some of the barium content. For example, strontium (Sr) can be included, and its content percent can be calculated in the same manner as the barium percent described herein in reference to Equation 6.
In some embodiments having x values <0.667 in, for example Formula 4, there may be conditions where rutile TiO2 can be added as a second crystallographic phase. Examples of such additions are described herein in greater detail. Further, some embodiments can include small amounts of acceptor dopants such as MnO2 or CeO2 added to the composition to, for example, prevent or reduce thermal reduction of the titanium from Ti4+ to Ti3+.
Table 1 lists various samples having various combinations of aluminum percent (Al %, as described in Equation 5), barium percent (Ba %, as described in Equation 6), strontium percent (Sr %, similar to the barium percent), lanthanum percent (La %, mole percent), cerium oxide weight percent (CeO2 w %), and titanium oxide or rutile weight percent (TiO2 w %). Table 1 also lists density values of selected ones of the samples. Empty cells, if any, correspond to values that are either not applicable or not available. It will be understood that each of the samples listed in Table 1 is based on Formula 9 (Ba4+x′Sm(2/3)[14+0.5y−x′]Ti18−yAlyO54), with the various percent values corresponding to substitutions of Ba or Sm, or introduction of second phase materials (e.g., TiO2).
Table 2 lists Q values for the same samples of Table 1, at or near f=1 GHz. Corresponding Qf values are also listed. Table 2 also lists dielectric constant values (∈′) corresponding to the listed approximately 1 GHz frequency values for selected ones of the samples. Table 2 also lists values of temperature coefficient of resonant frequency (τf) for selected ones of the samples. Empty cells, if any, correspond to values that are either not applicable or not available. For example, in Table 2, Sample Nos. 14, 15, 27, 29, 113, 115, 116 and 125 are samples for which various corresponding parameters are either not applicable or not available.
Table 3 lists Q values for some of the samples of Table 1, at or near f=3 GHz. Corresponding Qf values are also listed. Table 3 also lists dielectric constant values (∈′) corresponding to the listed approximately 3 GHz frequency values. Empty cells, if any, correspond to values that are either not applicable or not available.














TABLE 1












Density


Sample No.
Al %
Ba %
Sr %
La %
CeO2 w %
TiO2 w %
(g/cm3)






















1
100
0
0
2.75
0
0



2
100
0
0
2.75
0
0


3
100
0
0
2.75
0
0


4
100
0
0
2.75
0
0


5
100
0
0
2.75
0
0


6
100
0
0
2.75
0
0


7
100
0
0
2.75
0
0


8
75
0
0
0
0
0


9
75.1
24.8
0
0
0
0


10
50
0
0
0
0
0


11
50
25
0
0
0
0


12
25
0
0
0
0
0


13
24.9
24.9
0
0
0
0


14
0
0
0
0
0
25


15
0
25.1
0
0
0
25


16
75
25
0
0
0
25


17
50
0
0
0
0
25


18
50
25
0
0
0
25


19
25
0
0
0
0
25


20
25
25
0
0
0
25


21
25
0
0
0
0
12.5


22
25
25
0
0
0
12.5


23
75.1
24.8
0
0
0.25
0
5.453


24
50
25
0
0
0.5
0


25
24.9
24.9
0
0
0.75
0


26
0
25.1
0
0
0.75
25


27
0
25.1
0
0
0.875
12.5


28
24.9
24.9
0
0
0.558
25


29
24.9
24.9
0
0
0.658
12.5


30
74.2
48.06
0
2.8
0.25
0
5.896


31
49.85
25.09
0
5.78
0.5
0


32
24.98
24.91
0
8.89
0.75
0


33
0
24.92
0
12.14
0.875
0


34
24.98
24.91
0
8.89
0.75
25


35
24.98
24.91
0
8.89
0.75
12.5


36
74.75
25.34
0
2.84
0
0
5.916


37
49.68
24.91
0
5.82
0
0


38
24.67
24.8
0
8.92
0
0


39
0
24.92
0
12.14
0
25


40
0
24.92
0
12.14
0
12.5


41
24.67
24.8
0
8.92
0
25


42
24.67
24.8
0
8.92
0
12.5


43
9.93
24.9
0
5
0
0


44
9.93
25.1
0
10
0
0


45
31.28
24.88
0
5
0
0


46
31.28
24.88
0
10
0
0


47
50.02
24.84
0
5
0
0


48
50.02
24.84
0
10
0
0


49
70.07
25
0
5
0
0
5.74


50
70.07
25
0
10
0
0


51
89.95
25.87
0
5
0
0


52
89.95
25.87
0
10
0
0


53
9.93
24.9
0
2.5
0
0


54
31.28
24.88
0
2.5
0
0


55
50.02
24.84
0
2.5
0
0
5.76


56
70.07
25
0
2.5
0
0
5.74


57
89.95
25.87
0
2.5
0
0


58
10
31.99
0
5
0
0


59
10
31.99
0
10
0
0


60
29.8
33.8
0
5
0
0


61
29.8
33.8
0
10
0
0


62
49.6
37.06
0
5
0
0


63
49.6
37.06
0
10
0
0


64
69.4
45.02
0
5
0
0
5.7


65
69.4
45.02
0
10
0
0
5.7


66
89.23
82.2
0
5
0
0
5.64


67
89.23
82.2
0
10
0
0
5.66


68
10
31.99
0
2.5
0
0


69
29.8
33.8
0
2.5
0
0


70
49.6
37.06
0
2.5
0
0


71
69.4
45.02
0
2.5
0
0
5.75


72
89.23
82.2
0
2.5
0
0
5.67


73
74.2
48
0
10
0
0
5.77


74
74.2
48
0
10
0
10


75
74.2
0
48
10
0
0
5.81


76
74.2
48
0
20
0
0
5.78


77
74.2
48
0
30
0
0
5.77


78
74.2
48
0
40
0
0
5.67


79
74.75
25.35
0
10
0
0
5.8


80
74.75
25.35
0
10
0
10


81
74.75
0
25.35
10
0
0
5.8


82
74.75
25.35
0
20
0
0
5.79


83
74.75
25.35
0
30
0
0
5.77


84
74.75
25.35
0
40
0
0
5.71


85
70.06
25
0
10
0
0
5.76


86
70.06
25
0
10
0
10


87
70.06
0
25
10
0
0
5.82


88
70.06
25
0
20
0
0
5.66


89
70.06
25
0
30
0
0
5.73


90
70.06
25
0
40
0
0
5.73


91
89.25
82.3
0
10
0
0


92
89.25
82.3
0
10
0
10


93
89.25
0
82.3
10
0
0


94
89.25
82.3
0
20
0
0


95
89.25
82.3
0
30
0
0


96
89.25
82.3
0
40
0
0


97
69.35
45
0
10
0
0
5.76


98
69.35
45
0
10
0
10


99
69.35
0
45
10
0
0
5.79


100
69.35
45
0
20
0
0
5.73


101
69.35
45
0
30
0
0
5.76


102
69.35
45
0
40
0
0
5.64


103
50
0
0
5
0
0


104
50
0
0
5
0
10


105
50
12.5
0
5
0
0


106
50
12.5
0
5
0
10


107
50
25
0
5
0
0


108
50
25
0
5
0
10


109
50
37.5
0
5
0
0


110
50
37.5
0
5
0
10


111
50
50
0
5
0
0


112
50
50
0
5
0
10


113
50
75
0
5
0
0


114
50
75
0
5
0
10


115
50
100
0
5
0
0


116
50
100
0
5
0
10


117
66.67
0
0
5
0
0


118
66.67
0
0
5
0
10


119
66.67
25
0
5
0
0


120
66.67
25
0
5
0
10


121
66.67
50
0
5
0
0


122
66.67
50
0
5
0
10


123
66.67
75
0
5
0
0


124
66.67
75
0
5
0
10


125
66.67
100
0
5
0
0


126
66.67
100
0
5
0
10


127
83.33
50
0
5
0
10


128
83.33
100
0
5
0
0


129
83.33
100
0
5
0
10


130
70.06
25
0
40
0
0


131
70.06
25
0
40
0.067
0


132
70.06
25
0
40
0.033
0


133
70.06
25
0
40
0.067
0


134
70.06
25
0
40
0
0


135
70.06
25
0
40
0.133
0


136
50
20
0
0
0
8.333


137
50
20
0
0
0.067
8.333


138
50
20
0
0
0.067
8.333


139
25
25
0
0
0
8.333


140
25
25
0
0
0.067
8.333
5.61


141
25
25
0
0
0.033
8.333
5.61


142
25
25
0
0
0.067
8.333


143
25
25
0
10
0
8.333


144
25
25
0
10
0.067
8.333


145
25
25
0
10
0.033
8.333


146
25
25
0
10
0.067
8.333


147
50
27
0
0
0.067
10


148
50
29
0
0
0.067
10


149
50
31
0
0
0.067
10


150
50
33
0
0
0.067
10


151
50
35
0
0
0.067
10


152
50
37
0
0
0.067
10


153
50
39
0
0
0.067
10


154
50
41
0
0
0.067
10


155
50
43
0
0
0.067
10


156
50
45
0
0
0.067
10


157
70.06
25
.3GeO2
0
.067MnO2
0


158
70.06
25
.3GeO2
0
0.067
0


159
70.06
25
.3GeO2
40
.067MnO2
0


160
70.06
25
.3GeO2
40
0.067
0


161
70.06
25
0
50Nd2O3
0.067
0


162
70.06
25
0
50Nd2O3
.067MnO2
0


163
70.06
25
.3GeO2
50Nd2O3
0.067
0


164
70.06
25
.3GeO2
50Nd2O3
.067MnO2
0


165
25
25
.3GeO2
0
0.067
10


166
25
25
.3GeO2
10
0.067
10


167
25
25
0
10Nd2O3
0.067
0


168
25
25
.3GeO2
10Nd2O3
0.067
0


169
25
25
0
50Nd2O3
0.067
0


170
25
25
.3GeO2
50Nd2O3
0.067
0





















TABLE 2





Sample No.
Q (1 GHz)
f
Qf (1 GHz)
∈′ (1 GHz)
τF




















1
2170
1.156
2508.52




2
3170
1.172
3715.24




3
3420
1.111
3799.62




4
6580
1.089
7165.62




5
4770
1.045
4984.65




6
7300
1.013
7394.9




7
7830
0.949
7430.67




8
2620
1.092
2861.04




9
9510
1.104
10499.04




10
3600
1.054
3794.4




11
6720
1.052
7069.44




12
4410
1.016
4480.56




13
3600
1.0528
3790.08
81.8



14







15







16
1000
0.98
980
82



17
1500
0.9543
1431.45
81.9



18
4780
0.974
4655.72




19
1400
0.9484
1327.76
84.2



20
1500
0.9805
1470.75
79.7



21
1000
0.9929
992.9
78.4



22
1400
1.026
1436.4
73.8



23
9700
1.1895
11538.15

−41.61


24
8000
1.0859
8687.2
68.3



25
2500
1.0306
2576.5
76.6



26
3900
1.0723
4181.97
76.7



27







28
1000
0.9966
996.6
77.1



29







30
12000
1.0818
12981.6
63.1
−62.53


31
9400
1.0363
9741.22




32
9900
1.0109
10007.91




33
5200
1.0903
5669.56




34
5000
1.2524
6262




35
3800
1.3473
5119.74




36
11000
1.0839
11922.9
66
−61.19


37
9600
1.0446
10028.16




38
8000
0.9915
7932




39
6000
1.0312
6187.2




40
6300
1.0055
6334.65




41
8000
1.1036
8828.8




42
8000
1.0685
8548




43
7680
0.9718
7463.424




44
7668
0.9669
7414.1892




45
8742
1.0128
8853.8976




46
8734
1.0081
8804.7454




47
9910
1.0601
10505.591




48
9696
1.0502
10182.739




49
10923
1.0876
11879.855

−55.32


50
10580
1.0904
11536.432

−48.21


51
4352
1.1621
5057.4592




52
7031
1.2009
8443.5279




53
7079
1.0114
7159.7006




54
7885
1.1273
8888.7605




55
10224
1.0482
10716.797

−46.15


56
10780
1.1261
12139.358

−57.93


57
3674
1.1532
4236.8568




58
3556
0.9687
3444.6972




59
4647
0.9609
4465.3023




60
7770
1.0052
7810.404




61
7948
1.0043
7982.1764




62
9417
1.0411
9804.0387




63
9302
1.0517
9782.9134




64
10341
1.0823
11192.064

−54.1


65
10018
1.0909
10928.636

−46.83


66
10860
1.1288
12258.768

−62.16


67
10445
1.1151
11647.22

−55.87


68
2653
0.9673
2566.2469




69
6935
1.0049
6968.9815




70
9223
1.0384
9577.1632




71
10003
1.1293
11296.388

−58.02


72
11197
1.1336
12692.919

−65.23


73
9700
1.0987
10657.39
65.5
−50.34


74
4500
1.1571
5206.95
69.8



75
9300
1.0991
10221.63
66.3
−51.46


76
9400
1.1015
10354.1
67.8
−32.96


77
8200
1.0835
8884.7
69.5
−12.82


78
6600
1.1135
7349.1
70.5
15.09


79
10600
1.1003
11663.18
66
−52.13


80
3600
1.0643
3831.48
67.1



81
8800
1.1149
9811.12
65.8
−53.34


82
9800
1.09
10682
67.5
−36.93


83
8800
1.0905
9596.4
68.8
−16.24


84
7400
1.0616
7855.84
69.9
7.33


85
10300
1.1232
11568.96
65.8
−48.71


86
4300
1.0486
4508.98
69.3



87
8700
1.1725
10200.75
67
−51.36


88
10400
1.0536
10957.44
65.5
−32.12


89
9000
1.045
9405
68.9
−14.01


90
7600
1.0537
8008.12
71.9
9.81


91
9200
1.2902
11869.84
61.2



92
2600
1.088
2828.8
64.1



93
8000
1.1366
9092.8
61.5



94
9200
1.1044
10160.48
61.9



95
7500
1.1018
8263.5
62.8



96
6000
1.1165
6699
62.8



97
10000
1.0912
10912
66.9
−47.17


98
4800
1.0472
5026.56
71.9



99
9400
1.0952
10294.88
67.8
−49.31


100
9500
1.0742
10204.9
68.1
−29.03


101
8400
1.0607
8909.88
70.9
−8.75


102
6800
1.0476
7123.68
71.2
20.57


103
4300
1.0483
4507.69
70.8



104
2500
1.0174
2543.5
73.9



105
10300
1.0656
10975.68
68.7



106
2700
1.0132
2735.64
75.6



107
9850
1.0651
10491.235
69.2



108
7000
1.0099
7069.3
75.7



109
9000
1.0788
9709.2
70.1



110
6800
1.0302
7005.36
73.6



111
2000
1.0491
2098.2
71.9



112
4800
1.1632
5583.36
55



113







114
5700
1.0687
6091.59
66



115







116







117
4200
1.0897
4576.74
67.4



118
5600
1.0445
5849.2
67.3



119
10600
1.102
11681.2
65.5



120
1600
1.0285
1645.6
71.4



121
9700
1.102
10689.4
66.5



122
3200
1.0222
3271.04
72.5



123
1000
1.0881
1088.1
68.4



124
5100
1.0373
5290.23
68.2



125







126
4900
1.0799
5291.51
63.4



127
1600
1.0603
1696.48
66.7



128
1600
1.1628
1860.48
61.7



129
3700
1.0604
3923.48
67.4



130
6600
1.0502
6931.32
71.1



131
6900
1.0722
7398.18
71.1



132
6900
1.0661
7356.09
71.2



133
6800
1.0789
7336.52
71.4



134
6100
1.0704
6529.44
71.5



135
7000
1.0816
7571.2
69.6



136
6900
1.0419
7189.11
73.4



137
7300
1.037
7570.1
73.4



138
6900
1.0293
7102.17
72.9



139
8800
1.0313
9075.44
72.9



140
9900
1.0287
10184.13
72.9
−2.6


141
9900
1.0244
10141.56
73
−1.86


142
9600
1.0327
9913.92
72.7



143
8000
1.0281
8224.8
74.6



144
8600
1.0266
8828.76
74.4



145
8200
1.0362
8496.84
74.4



146
7900
1.0366
8189.14
74.4



147
1700
1.1102
1887.34
63.9



148
2000
1.1221
2244.2
64



149
2600
1.1132
2894.32
64.2



150
3000
1.1339
3401.7
62.8



151
3500
1.0861
3801.35
65.4



152
4300
1.0872
4674.96
64.3



153
5600
1.0834
6067.04
65.2



154
5800
1.0893
6317.94
65.5



155
5800
1.0991
6374.78
63.6



156
5000
1.0901
5450.5
63.3



157
9000
1.1791
10611.9
64.3



158
9200
1.1796
10852.32
63.8



159
6200
1.1302
7007.24
71.2



160
6200
1.1229
6961.98
71.1



161
10200
1.1065
11286.3
64



162
10300
1.1121
11454.63
65.3



163
10400
1.1118
11562.72
64.3



164
9500
1.124
10678
67



165
3800
1.1339
4308.82
63.8



166
6000
1.1159
6695.4
60.3



167
5600
1.0165
5692.4
77.6



168
6700
1.0823
7251.41
75.2



169
8800
1.0029
8825.52
80.4



170
8500
1.0377
8820.45
79.5




















TABLE 3





Sample No.
Q (3 GHz)
f
Qf (3 GHz)
∈′ (3 GHz)



















23
3669
3.5075
12869.018
54.69


30
4104
3.301
13547.304
65.06


36
4080
3.283
13394.64
65.81


49
3981
3.3071
13165.565
64.3


50
3952
3.2981
13034.091



55
3619
3.1984
11575.01
68.8


56
3988
3.315
13220.22
63.97


64
3808
3.3186
12637.229
63.85


65
3746
3.2934
12337.076
64.86


66
4175
3.4485
14397.488
59.07


67
3986
3.4196
13630.526
60.08


71
3807
3.3019
12570.333
64.52


72
4161
3.4473
14344.215
59.19


73
3726
3.2956
12279.406
64.89


75
4055
3.273
13272.015
65.84


76
3784
3.2418
12266.971
67.04


77
3548
3.1944
11333.731
69.1


78
3106
3.1836
9888.2616
69.64


79
4152
3.2889
13655.513
65.19


81
3890
3.2922
12806.658
65.06


82
3915
3.243
12696.345
67.01


83
3725
3.2149
11975.503
68.29


84
3319
3.1924
10595.576
69.25


85
4121
3.2855
13539.546
65.33


87
3941
3.2575
12837.808
66.46


88
3864
3.2943
12729.175
65.08


89
3594
3.2154
11556.148
68.36


90
3279
3.158
10355.082
70.9


97
3973
3.2739
13007.205
65.89


99
3955
3.2538
12868.779
66.7


100
3635
3.239
11773.765
67.35


101
3520
3.1777
11185.504
70.03


102
2975
3.1723
9437.5925
70.27


140
3776
3.1235
11794.336
72.7


141
3793
3.1231
11845.918
72.66









As described herein, in some radio-frequency (RF) applications such as low-frequency (700 MHz-1 GHz) microwave applications, materials with dielectric constant values greater than 60 and having Qf (product of Q and frequency f) values greater than 10,000 can be desirable. Among the non-limiting examples listed in Tables 1-3, a number of configurations can include such a combination of relatively high dielectric constant (e.g., greater than 60) and relatively high Qf (e.g., greater than 10,000) at or near such a low-frequency range of 700 MHz-1 GHz. Table 4 lists such configurations selected from the list of Tables 1-3.
















TABLE 4





Sample No.
Al %
Ba %
Sr %
La %
CeO2 w %
TiO2 w %
Qf (1 GHz)
ε′
τF
























9
75.1
24.8
0
0
0
0
10499




23
75.1
24.8
0
0
0.25
0
11538

−41.61


30
74.2
48.06
0
2.8
0.25
0
12982
63.1
−62.53


32
24.98
24.91
0
8.89
0.75
0
10008


36
74.75
25.34
0
2.84
0
0
11923
66
−61.19


37
49.68
24.91
0
5.82
0
0
10028


47
50.02
24.84
0
5
0
0
10506


48
50.02
24.84
0
10
0
0
10183


49
70.07
25
0
5
0
0
11880

−55.32


50
70.07
25
0
10
0
0
11536

−48.21


55
50.02
24.84
0
2.5
0
0
10717

−46.15


56
70.07
25
0
2.5
0
0
12139

−57.93


64
69.4
45.02
0
5
0
0
11192

−54.1


65
69.4
45.02
0
10
0
0
10929

−46.83


66
89.23
82.2
0
5
0
0
12259

−62.16


67
89.23
82.2
0
10
0
0
11647

−55.87


71
69.4
45.02
0
2.5
0
0
11296

−58.02


72
89.23
82.2
0
2.5
0
0
12693

−65.23


73
74.2
48
0
10
0
0
10657
65.5
−50.34


75
74.2
0
48
10
0
0
10222
66.3
−51.46


76
74.2
48
0
20
0
0
10354
67.8
−32.96


79
74.75
25.35
0
10
0
0
11663
66
−52.13


82
74.75
25.35
0
20
0
0
10682
67.5
−36.93


85
70.06
25
0
10
0
0
11569
65.8
−48.71


87
70.06
0
25
10
0
0
10201
67
−51.36


88
70.06
25
0
20
0
0
10957
65.5
−32.12


91
89.25
82.3
0
10
0
0
11870
61.2


94
89.25
82.3
0
20
0
0
10160
61.9


97
69.35
45
0
10
0
0
10912
66.9
−47.17


99
69.35
0
45
10
0
0
10295
67.8
−49.31


100
69.35
45
0
20
0
0
10205
68.1
−29.03


105
50
12.5
0
5
0
0
10976
68.7


107
50
25
0
5
0
0
10491
69.2


119
66.67
25
0
5
0
0
11681
65.5


121
66.67
50
0
5
0
0
10689
66.5


140
25
25
0
0
0.067
8.333
10184
72.9
−2.6


141
25
25
0
0
0.033
8.333
10142
73
−1.86


157
70.06
25
.3GeO2
0
.067MnO2
0
10612
64.3


158
70.06
25
.3GeO2
0
0.067
0
10852
63.8


161
70.06
25
0
50Nd2O3
0.067
0
11286
64


162
70.06
25
0
50Nd2O3
.067MnO2
0
11455
65.3


163
70.06
25
.3GeO2
50Nd2O3
0.067
0
11563
64.3


164
70.06
25
.3GeO2
50Nd2O3
.067MnO2
0
10678
67









In Table 4, some of the listed samples do not have measured dielectric constant (∈′) values. However, and as described herein in reference to Formula 1, tungsten bronze based materials, including the samples of Table 4, will tend to have dielectric constant values that are greater than 50.
Also in Table 4, some of the measured values of temperature coefficient of resonant frequency (τf) are not listed. Among the samples whose τf values are listed, all of them are negative, mainly due to the Sm being the primary lanthanide. As described herein, such negative values of τf can be compensated by introduction of other lanthanides (e.g., Nd, Pr, Ce and La) having positive τf values.
For example, in Table 4, samples 56, 49, 50 and 88 all have the same 70% aluminum percent value and 25% barium percent value, but have increasing lanthanum content (La %) of 2.5%, 5%, 10% and 20%, respectively. For the same samples in the same order, one can see that the τf values (−57.93, −55.32, −48.21 and −32.12) become less negative as La % value increases.
In some embodiments, materials having one or more features as described herein can be implemented as microwave dielectric materials. As described herein, such microwave dielectric materials can be configured to have dielectric constant values greater than 60. When combined with improved Q performance and temperature compensation capability, such microwave dielectric materials can be desirable for RF applications such as Long-Term Evolution (LTE) applications in which filters can benefit from reduced sizes.
As described herein, substituting aluminum (Al) for at least some of the titanium (Ti) in the octahedral sites of a tungsten bronze material can yield some or all the foregoing desirable properties. Such substitutions can be effectuated in cost-effective manner.
As also described herein, lanthanides such as Sm and/or Nd can be utilized to achieve temperature compensated ceramic bodies. Table 5 lists additional examples of compositions that show, among others, how temperature coefficient of resonant frequency (τf) can be adjusted by different combinations of Sm and Nd, and/or different substitutions of Ti with Al.











TABLE 5







Dielec-





Den-
tric





sity
Con-

Qf (at


Sample
(g/cm3)
stant
τF
3 GHz)



















Ba4Sm9.6Ti17.2Al.8O54
5.62
66.33
−50.38
11641


Ba4Nd9.46667Ti17.6Al.4O54
5.69
79.5
48.17
16073


Ba4Nd9.6Ti17.2Al.8O54
5.67
75.12
32.07
15298


Ba4Nd9.7333Ti16.8Al1.2O54
5.70
70.07
13.76
14635


Ba4Nd9.8666Ti16.4Al1.6O54
5.35
60.22
8.5
16028


Ba4Nd9.0667Y.4Ti17.6Al.4O54
5.63
78.42
26.36
13936


Ba4Nd8.8Y.8Ti17.2Al.8O54
5.57
72.3
5.85
14673


Ba4Sm7.5733Nd1.8933Ti17.6Al.4O54
5.77
80.27
20.23
15653


Ba4Sm5.76Nd3.84Y.8Ti17.2Al.8O54
5.81
74.65
−7.26
16534









At least some of the compositions listed in Table 5 are more specific examples of the samarium (Sm) based compositions described herein in reference to Formula 9 (Ba4+x′Sm(2/3)[14+0.5y−x′]Ti18−yAlyO54). In the example context of some of Sm being replaced with neodymium (Nd), such a formula can be expressed as

Ba4(Nd1−xSmx)28/3+y/3Ti18−yAlyO54.  (10)

In Formula 10, x can be referred to as Sm content, and y can be referred to as Al content.

As described in reference to Table 5, temperature coefficient of resonant frequency (τf) can be tuned by different combinations of Sm and Nd, and/or different substitutions of Ti with Al. Table 6 lists various examples of combinations of the Sm content (x) and the Al content (y) in reference to Formula 10.










TABLE 6





Sample
Qf (at 1 GHz)
Qf (at 3 GHz)
∈′


















x = 0.2, y = 1.6
9796
15907
65.61


x = 0.4, y = 1.2
10210
14448
70.02


x = 0.6, y = 0.8
9436
13107
73.07


x = 0.8, y = 0.4
7688
12021
76.46


x = 0.6, y = 0.4
8824
13247
77.81


x = 0.4, y = 0.8
10302
15395
73.96


x = 0.2, y = 1.2
10151
15638
71.22


x = 0.4, y = 0.4
9068
15593
70.38


x = 0.2, y = 0.8
9154
14851
75.38


x = 0.355, y = 0.68
10500
15321
75.2









For the samples listed in Table 6, their values of τf are generally in a range of −50 to 0 or 0 to 50. Accordingly, such samples can be utilized to estimate a plane in which τf is zero or close to zero, if such tuning is desired. For the example described in reference to Formula 10 and Table 6, such a τf=0 plane can be along an approximate line between points (y≈0, x≈0.77) and (y≈1.8, x≈2) when y (Al content) is on the horizontal axis and x (Sm content) is on the vertical axis. In such a system, one can see that the example configuration of (x=0.355, y=0.68) (last example in Table 6) yields relatively high values of dielectric constant (75.2) and Qf (10500 at 1 GHz), while having τf that is tuned to a value close to zero. It will be understood that other systems having one or more features as described herein can also be tuned in a similar manner.
In some embodiments, Q value of a system can be adjusted (e.g., enhanced) by adjusting the Sm content (in the example context of the system of Formula 10), adding elements/compounds, and/or substituting elements/compounds. In the context of the example system of Formula 10, a more specific example can be represented by Ba4Nd6.16Sm3.4Ti17.32Al0.68O54. Examples of adjustments to such a system, and the resulting values of Qf, are listed in Table 7. If a Qf value greater than 10000 is desired, one can see that, for example, substituting Ge0.1 for Ti0.1 yields a relatively high Qf value of approximately 12300 (at 1 GHz).







TABLE 7





Ba4Nd6.16Sm3.4Ti17.32 Al0.68O54


















x = 0.6
Qf = 8467 (1 GHz)



x = 0.75
Qf = 8993 (1 GHz)



1% Na2O added
Qf = 9943 (1 GHz)



1% K2O added
Qf = 7597 (1 GHz)



+2% Ba2Ti9O20
Qf = 9982 (1 GHz)



Sn.05 for Ti.05
Qf = 10040 (1 GHz)



(Ba3.6Sr0.4)
Qf = 8958 (1 GHz)



Mg.34Ti.34 for Al.68
Qf = 8101 (1 GHz)



Zn.34Ti.34 for Al.68
Qf = 6396 (1 GHz)



Ge.1 for Ti.1
Qf = 12300 (1 GHz)



Fe.68 for Al.68
Qf = 4610



Mn.68 for Al.68
Qf = 8045



Mg.34Ge.34 for Al.68
Qf = 8509



Zn.34Ge.34 for Al.68
Qf = 10044









FIGS. 1 and 2 show examples of microwave devices that can be formed from materials having one or more features as described herein. FIG. 1 shows that in some embodiments, a ceramic puck 100 can include a material as described herein so as to yield desirable properties such as a high dielectric constant (e.g., greater than 60) and a high Qf value (e.g., greater than 10,000) at relatively low frequencies (e.g., 700 MHz-1 GHz). Such a puck 100 can be implemented in a cylindrical shape having a diameter Dr and a height Lr. Such a puck 100 can be utilized as a microwave resonator.
FIG. 2 shows that in some embodiments, a ceramic puck 100 having one or more features as described herein can include a center aperture dimensioned to allow, for example, tuning of the ceramic puck when utilized as a microwave resonator. The aperture is shown to have a diameter of dr. The overall diameter Dr and the height Lr may or may not be the same as the solid ceramic puck counterpart.
FIG. 3 shows a tunable microwave resonator configuration 110. A ceramic puck 100 similar to the example of FIG. 2 is shown to be supported by a support structure. A ceramic tuning element can be dimensioned to fit within the aperture of the ceramic puck 100; and tuning can be achieved by the extent of insertion of the tuning element into the aperture.
FIG. 4 shows an example of a cavity filter 120 having a plurality of cavities 122 arranged between RF ports 124, 126. Each cavity 122 can be dimensioned to receive a resonator puck (e.g., 100 in FIGS. 1 and 2). Such a resonator puck may or may not be tunable. The resonators in their respective cavities can pass successively filtered RF signal through slots formed between neighboring cavities.
FIG. 5 shows an example of an RF system that can utilize one or more of the filter device 120 of FIG. 4. For example, the filter device of FIG. 4 can be implemented as a dielectric narrowband filter 120 between an antenna and a filter diplexer. The filter diplexer can be configured to provide a filtered signal to a low-noise amplifier (LNA) to be further processed by an Rx filter, a mixer that generates an intermediate-frequency (IF) with use of a local oscillator (L.O.) and an L.O. filter, and a baseband subsystem. The filter diplexer can also be configured to route an amplified RF signal from a power amplifier (PA) to the antenna for transmission. The power amplifier can be provided with an RF signal from an up converter passed through a Tx filter.
FIGS. 6-10 show examples of how dielectric materials and/or devices having one or more features as described herein can be fabricated. FIG. 6 shows a process 20 that can be implemented to fabricate a ceramic material having one or more of the foregoing properties. In block 21, powder having one or more features as described herein can be prepared. In block 22, a shaped object can be formed from the prepared powder. In block 23, the formed object can be sintered. In block 24, the sintered object can be finished to yield a finished ceramic object having one or more desirable properties.
In implementations where the finished ceramic object is part of a device, the device can be assembled in block 25. In implementations where the device or the finished ceramic object is part of a product, the product can be assembled in block 26.
FIG. 6 further shows that some or all of the steps of the example process 20 can be based on a design, specification, etc. (collectively depicted as block 27). Similarly, some or all of the steps can include or be subjected to testing, quality control, etc. (collectively depicted as block 28).
In some implementations, powder prepared in the powder preparation step (block 21) of FIG. 6 can be formed into different shapes by different forming techniques. By way of an example, FIG. 7 shows a process 50 that can be implemented to press-form a shaped object from a powder material prepared as described herein. In block 51 of FIG. 7, a powder as described herein can be provided. In block 52 of FIG. 7, a shaped die can be filled with a desired amount of the powder. In FIG. 8, configuration 60 shows the shaped die as 61 that defines a volume 62 dimensioned to receive the powder 63 and allow such power to be pressed. In block 53 of FIG. 7, the powder in the die can be compressed to form a shaped object. Configuration 64 of FIG. 8 shows the powder in an intermediate compacted form 67 as a piston 65 is pressed (arrow 66) into the volume 62 defined by the die 61. In block 54 of FIG. 7, pressure can be removed from the die. In block 55 of FIG. 7, the die (61 in FIG. 8) can be opened so as to expose the volume (62 in FIG. 8) by removing the piston (65 in FIG. 8). Configuration 68 of FIG. 8 shows the exposed volume (62) of the open die (61) thereby allowing the formed object 69 to be removed from the die. In block 56 of FIG. 7, the formed object (69 in FIG. 8) can be removed from the die (61 in FIG. 8). In block 57 of FIG. 7, the formed object can be stored for further processing.
In some implementations, formed objects fabricated as described herein can be sintered to yield desirable physical properties as ceramic devices. FIG. 9 shows a process 70 that can be implemented to sinter such formed objects. In block 71, formed objects can be provided. In block 72, the formed objects can be introduced into a kiln. In FIG. 10, a plurality of formed objects 69 are shown to be loaded into a sintering tray 80. The example tray 80 is shown to define a recess 81 dimensioned to hold the formed objects 69 on a surface 82 so that the upper edge of the tray is higher than the upper portions of the formed objects 69. Such a configuration allows the loaded trays to be stacked during the sintering process. The example tray 80 is further shown to define cutouts 83 at the side walls to allow improved circulation of hot gas at within the recess 81, even when the trays are stacked together. FIG. 10 further shows a stack 84 of a plurality of loaded trays 80. A top cover 85 can be provided so that the objects loaded in the top tray generally experience similar sintering condition as those in lower trays.
In block 73 of FIG. 9, heat can be applied to the formed objects so as to yield sintered objects. Such application of heat can be achieved by use of a kiln. In block 74 of FIG. 9, the sintered objects can be removed from the kiln. In FIG. 10, the stack 84 having a plurality of loaded trays is depicted as being introduced into a kiln 87 (stage 86a). Such a stack can be moved through the kiln (stages 86b, 86c in FIG. 10) based on a desired time and temperature profile. In stage 86d of FIG. 10, the stack 84 is depicted as being removed from the kiln so as to be cooled.
In block 75 of FIG. 9, the sintered objects can be cooled. Such cooling can be based on a desired time and temperature profile. In block 76 of FIG. 9, the cooled objects can undergo one or more finishing operations. In block 77 of FIG. 9, one or more tests can be performed.
Heat treatment of various forms of powder and various forms of shaped objects are described herein as calcining, firing, annealing, and/or sintering. It will be understood that such terms may be used interchangeably in some appropriate situations, in context-specific manners, or some combination thereof.
Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising,” and the like are to be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” The word “coupled”, as generally used herein, refers to two or more elements that may be either directly connected, or connected by way of one or more intermediate elements. Additionally, the words “herein,” “above,” “below,” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application. Where the context permits, words in the above Detailed Description using the singular or plural number may also include the plural or singular number respectively. The word “or” in reference to a list of two or more items, that word covers all of the following interpretations of the word: any of the items in the list, all of the items in the list, and any combination of the items in the list.
The above detailed description of embodiments of the invention is not intended to be exhaustive or to limit the invention to the precise form disclosed above. While specific embodiments of, and examples for, the invention are described above for illustrative purposes, various equivalent modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize. For example, while processes or blocks are presented in a given order, alternative embodiments may perform routines having steps, or employ systems having blocks, in a different order, and some processes or blocks may be deleted, moved, added, subdivided, combined, and/or modified. Each of these processes or blocks may be implemented in a variety of different ways. Also, while processes or blocks are at times shown as being performed in series, these processes or blocks may instead be performed in parallel, or may be performed at different times.
The teachings of the invention provided herein can be applied to other systems, not necessarily the system described above. The elements and acts of the various embodiments described above can be combined to provide further embodiments.
While some embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosure. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the disclosure. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosure.

## Claims

1. A composition comprising a material with a formula Ba4+xSm(2/3)(14−x+0.5y)Ti18−yAlyO54, the quantity y being in a range 0<y<2, the quantity x being in a range 0<x<2−y.

2. The composition of claim 1 wherein the quantity x is in a range 0<x<1−0.5y corresponding to barium content being in a range of 0% to 50%.

3. The composition of claim 1 wherein the quantity y is approximately 0.5 and the quantity x is in a range from approximately 0.01 to approximately 1.0.

4. The composition of claim 1 wherein the quantity y is approximately 1.0 and the quantity x is in a range from approximately 0.01 to approximately 0.5.

5. The composition of claim 1 wherein the quantity y is approximately 1.4 and the quantity x is in a range from approximately 0.01 to approximately 0.3.

6. The composition of claim 1 wherein at least some of the Sm is substituted by another lanthanide.

7. The composition of claim 6 wherein the other lanthanide includes La, Ce, Pr, Nd or Gd.

8. The composition of claim 6 wherein the other lanthanide substitutes up to approximately 50 atomic percent of the Sm.

9. The composition of claim 8 wherein the other lanthanide is La or Nd.

10. The composition of claim 1 wherein at least some of the Ba is substituted by Sr.

11. The composition of claim 1 further comprising a minor additive including manganese oxide, manganese carbonate, cerium oxide, copper oxide, germanium oxide, silica or gallium oxide.

12. The composition of claim 1 further comprising a high Q second phase material.

13. A dielectric resonator comprising a ceramic device configured as a microwave resonator, the ceramic device including a material with a formula Ba4+xSm(2/3)(14−x+0.5y)Ti18−yAlyO54, the quantity y being in a range 0<y<2, the quantity x being in a range 0<x<2−y.

14. The dielectric resonator of claim 13 wherein the material has a dielectric constant value that is greater than 60 for frequencies less than or equal to 1 GHz.

15. The dielectric resonator of claim 14 wherein the dielectric constant value is in a frequency range that is greater than or equal to 700 MHz and less than or equal to 1 GHz.

16. The dielectric resonator of claim 14 wherein the material has a Qf value that is greater than 10,000, the quantity Q being a quality factor, the quantity f being a frequency expressed in GHz.

17. A method for fabricating a tungsten bronze material, the method comprising:
in a material having rhombic (A1) sites, pentagonal (A2) sites, and titanium (Ti) in octahedral sites, substituting aluminum (Al) for at least some of the titanium (Ti) in the respective octahedral sites to provide a dielectric constant value greater than 60 and a Qf value greater than 10,000 at a frequency (f), with the quantity Q being a quality factor, and the quantity f being a frequency expressed in GHz and less than 1 GHz; and
adjusting contents of the A1 sites and the A2 sites to compensate for charge imbalance resulting from the aluminum substitution of titanium.

18. The method of claim 17 wherein the tungsten bronze material is represented by a formula [A2]4[A1]10Ti18−yAlyO54.

19. The method of claim 18 wherein substantially all of the A2 sites are occupied by barium (Ba) and at least some of the A1 sites are occupied by samarium (Sm), such that the adjusting includes adding x formula unit of Ba and (2⁄3)x formula unit of Sm to the A1 sites.

20. The method of claim 19 further comprising substituting at least some of the samarium with another lanthanide (Ln) to provide a temperature coefficient of resonant frequency (τf) that is less negative.