The poor sinterability and intrinsically positive τf of BaZr(PO4)2 ceramics were addressed by introducing ZnO as a sintering aid and property modifier. In a conventional solid-state reaction route, ZnO promoted liquid-phase sintering through the in situ formation of BaZn2(PO4)2, enabling near-full densification (>99% relative density) at 1250 °C. The ZnO content strongly affected phase evolution, microstructure, and microwave dielectric properties. The Q×f value reached a maximum at ∼4 wt% ZnO and then decreased because of losses associated with the secondary phase and increased grain-boundary density. Notably, τf could be systematically tuned from positive to negative values through compensation by the negative-τf BaZn2(PO4)2 phase. The optimized composition (4 wt% ZnO) exhibited εr ≈ 10.1, Q×f ≈ 36,300 GHz, and τf ≈ +0.4 ppm/°C. These results identify a promising microwave dielectric material that can be densified at a lower temperature and establish a practical strategy for tailoring τf in phosphate ceramics through controlled secondary-phase formation.

In this study, CaY2-xMxGe3O10 (M = Sm, Yb) ceramics with a P21/c space group were synthesised. Sm3 + can fully substitute Y3+, whereas the solid solubility limit of Yb3+ lies between 0.4 and 0.5. The corrected dielectric constant (epsilon r-corr) follows the trend of epsilon r-cal predicted based on the P-V-L theory, but is different with alpha TD/Vm in CaY2-xSmxGe3O10 (1.2/x/2), where significant reductions in distortion of [YO7] (Ave(delta Y-O)). The Q & times;f values, varying from 43,360 + 220 GHz to 113,620 + 680 GHz, are primarily governed by Ut, P.F., and Ea. The tau f, varying from-9.6 + 0.1 ppm/degrees C to-217.6 + 2.0 ppm/degrees C, is influenced by both Ave(delta Y-O) and fractional contribution of Ge-O bonds to overall susceptibility (chi(Ge-O)/chi). Notably, CaY1.6Yb0.4Ge3O10 ceramics exhibit a near-zero tau f (-9.6 + 0.1 ppm/degrees C) with epsilon r = 10.36 + 0.01 and Q & times;f = 92,540 + 560 GHz. CaY1.7Yb0.3Ge3O10 achieves high Q & times;f of 113,620 + 680 GHz. CaY0.8Sm1.2Ge3O10 ceramic demonstrates epsilon r = 10.31 + 0.01, Q & times;f = 50,510+250 GHz, and tau f =-217.6 + 2.0 ppm/degrees C.

Ca1–xMgxY2Ge3O10 ceramics were synthesised using the solid-state reaction method. XRD analysis reveals that the solid solubility limit of Mg2+ in Ca1–xMgxY2Ge3O10 lies between x = 0.15 and 0.20. Multiple characterisation approaches, including Phillips–van Vechten–Levine theory and bond valence analysis, were employed to systematically elucidate the crystal structure and microwave dielectric properties. TEM analysis revealed a distinct superlattice structure in the material, characterised by an increased density of (001) planes along the [100] zone axis. The presence of superlattice in Ca0.9Mg0.1Y2Ge3O10 gives rise to a higher degree of lattice ordering, thereby reducing the intrinsic loss. The corrected dielectric constant shows a trend opposite to the αDT/Vm from Clausius–Mossotti (C–M) equation, primarily because of the rattling effect induced by Mg2+ substitution, which limits the applicability of the C–M equation. The intrinsic loss of CaY2Ge3O10 was assessed by far-infrared spectroscopy. Key factors governing the microwave dielectric properties include total lattice energy (Ut), ion activation energy (Ea), and packing fraction (P.F.), which collectively determine the variation in Q×f, whereas the average distortion of Y–O bonds (Ave(δY–O)), the rattling effect and proportion of Ge–O bonds in total polarizability (χ(Ge–O)/χ), primarily affect τf. The Ca0.9Mg0.1Y2Ge3O10 ceramic exhibits an enhanced Q×f, with microwave dielectric properties of εr = 10.1, Q×f = 106,440 GHz, and τf = −27.1 × 10−6 °C−1. At x = 0.15, a reduced Ave(δY–O), a maximum χ(Ge–O)/χ, and a stronger rattling effect are observed, leading to a near-zero τf of −9.7 × 10−6 °C−1, with εr = 10.3 and Q×f = 91,920 GHz.

CaY2Ge3-xSixO10 ceramics were fabricated employing a conventional solid-state reaction route. X-ray diffraction analysis confirmed that the solid solubility limit of Si4+ ions in the CaY2Ge3-xSixO10 system (space group P21/c) lies between x = 0.45 and x = 0.6. When x = 0.6, Y2Si2O7 and Ca2Y3Si3O13 form as secondary phases, adversely affecting the microwave dielectric properties. The corrected dielectric constant (epsilon r-corr) exhibits an opposite trend to alpha TD/Vm derived from the Clausius-Mossotti (C-M) equation. This discrepancy arises because the substitution of Si4+ induces a rattling effect that enhances polarisability, rendering the C-M equation unsuitable for describing the dielectric behaviour of CaY2Ge3-xSixO10 ceramics. The variation in Q & times;f is primarily determined by the Ut and Ea, which exhibit similar compositional trends, while the packing fraction (P.F.) serves as a secondary factor. The highest Q & times;f of 125,720 GHz for CaY2Ge3-xSixO10 is achieved at x = 0.3, coinciding with the maximum Ut and a relatively high P.F. The tau f is mainly governed by the average Y-O bond distortion (Ave(delta Y-O)) and the rattling effect. At x = 0.3, Ave(delta Y-O) reaches its minimum, corresponding to the lowest bond valence and the strongest rattling effect, both of which contribute to shifting tau f in the positive direction towards a near-zero value. Ultimately, the CaY2Ge2.7Si0.3O10 ceramic achieves simultaneous optimisation of Q & times;f and tau f, exhibiting epsilon r = 10.1, Q & times;f = 125,720 GHz, and tau f = -4.5 ppm/degrees C.

As communication technologies advance toward high frequency bands, demand for low-temperature co-fired ceramic (LTCC) materials with low dielectric constants (epsilon r) and high quality factors (Q & times;f) continues to surge. In this work, ZnO-Al2O3-B2O3-SiO2 (ZABS) glass-ceramics were prepared using water-quenching followed by solidstate sintering. The effect of Zn/Si ratio on crystallization activation energy, sintering behavior, phase evolution, microstructure, and dielectric properties of glass-ceramics were researched. Results indicated that the crystallization tendency of glass-ceramics reduces with the Zn/Si ratio decreases from 2 to 1.38 because of the enhances glass network stability resulting from increases SiO2 content. However, a further decrease in the Zn/Si ratio leads to intensified crystallization tendency, which is caused by the occurrence of phase separation in the glass. All samples achieve densification in the range of 875-925 degrees C, with Zn2SiO4 as the main crystalline phase. Dielectric properties are significantly improved by decreasing the ZnO content and increasing the SiO2 content. The glass-ceramics with Zn/Si =1.38 sintered at 875 degrees C/2 h exhibits excellent performance: epsilon r = 5.3, Q & times;f = 28200 GHz (at 15.73 GHz), a temperature coefficient of resonant frequency (tau f) of-33 ppm/degrees C, and a flexural strength of 119 MPa. These excellent dielectric properties make the developed glass-ceramics promising candidates for future LTCC applications.

Microwave dielectric ceramics, as key materials in the field of 5 G/6 G telecommunication. Their temperature–frequency characteristics and flexural strength are crucial properties when used as dielectric substrates. Materials exhibiting a near-zero temperature coefficient of resonant frequency (τf) and high flexural strength are extremely rare. Herein, we report microwave dielectric ceramics (LaAl)1−x(SrTi)xTi2Al8O19 (0 ≤ x ≤ 1.0) with high flexural strength. The substitution positions and sequences of (SrTi)6 + were determined based on the Rietveld refinement and X-ray diffraction patterns. Bond valence and octahedral distortion calculation indicate that there is a significant distortion in LaTi2Al9O19. The distortion can be effectively reduced by introducing (SrTi)6+, with a larger relative radius, to replace (LaAl)6+, achieving near-zero τf while maintaining high flexural strength (σf): relative permittivity εr = 18.48 ± 0.07, Q×f = 17,380 ± 300 GHz @8.34 GHz, τf = +1.61 ± 0.27 ppm °C−1 and σf = 194.57 MPa. This study provides a novel candidate material for the next-generation of millimeter-wave communication devices.

In this study, ZnO–Al2O3–B2O3–SiO2 (ZABS) glass–ceramics were successfully prepared using water-quenching followed by solid-state sintering. The effects of B2O3 contents on the crystallization behavior, sintering characteristics, microstructure, and dielectric properties of glass–ceramics were investigated by differential scanning calorimeter (DSC), Fourier transform infrared spectrometer (FTIR), X-ray diffractometer (XRD), scanning electron microscope (SEM) and network analyzer. The results showed that increasing the B2O3 contents consumes the free oxygen provided by Zn2+ ions in the glass network, converting [BO3] into [BO4] units and enhancing the glass network stability. Simultaneously, the presence of [BO3] units reduces the glass softening point and crystallization activation energy. The dielectric performance of ZABS glass–ceramics depends on the degree of densification and crystallization. Among them, excellent dielectric properties with εr = 5.36 and Q × f = 32,200 GHz were obtained for the samples containing 12 mol

SrZn0.8Mg0.2Si3O8 ceramics capable of rapid densification under atmospheric pressure, while maintaining excellent microwave dielectric properties were investigated. In-situ scanning electron microscopy and high-resolution transmission electron microscopy confirm the formation of a liquid phase during sintering and clarify its chemical composition. Rapid densification originates from intrinsic generation of this liquid phase in SrZn0.8Mg0.2Si3O8 during the sintering process. Because the liquid phase is produced internally, most of it spontaneously crystallizes into the parent phase during cooling. Therefore, the final microstructure consists predominantly of the SrZn0.8Mg0.2Si3O8 phase with only a small residual amorphous phase. SrZn0.8Mg0.2Si3O8 ceramics thus exhibit excellent microwave dielectric properties (epsilon r = 6.07 +/- 0.02, Q & times;f = 69,350 +/- 650 GHz (f = 16.37 GHz), tau f =-27.6 +/- 1.4 & times; 10-6 degrees C-1, holding time(H.T.) =1 min), which are superior to those of conventional composite ceramics that rely on added low-melting-point oxides to induce liquid-phase sintering. In addition, rapid densification enables grain refinement while maintaining high relative density. This microstructural feature improves mechanical strength and electrical breakdown strength and suppresses long range ionic diffusion during heterogeneous cofiring integration. (c) 2026 The Authors. Published by Elsevier B.V. on behalf of The Chinese Ceramic Society. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

The feldspar-based microwave dielectric ceramic with low relative permittivity (sr) and excellent mechanical properties has attracted much attention in the fifth-generation wireless communication technology. In this work, a series of microwave dielectric ceramic SrAl2-xGaxSi2O8 (0.1 <= x <= 2.0) was synthesized using the traditional solid-state method. X-ray diffraction pattern indicates that Ga3+ can be dissolved into Al3+, forming a solid solution. Meanwhile, substitution of Ga3+ for Al3+ can promote the space group transition from I2/c (0.1 <= x <= 1.4) to P21/a (1.6 <= x <= 2.0) with coefficient of thermal expansion (CTE) increasing from 2.9x10-6 degrees C-1 to 5.2x10-6 degrees C-1. During this substitution, the phase transition can significantly improve the structural symmetry to enhance the dielectric properties and mechanical properties. Rietveld refinement results indicate that Ga3+ averagely occupied four Al3+ compositions to form solid solution. All ceramics have a dense microstructure and high relative density above 95%. An ultralow sr of 5.8 was obtained at x=1.6 composition with high quality factor (Qxf) of 50700 GHz and negative temperature coefficients of resonant frequency (zf) of approximately -35x10-6 degrees C-1. The densification temperature can be reduced to 940 degrees C by adding 4% (in mass) LiF, resulting in good chemical compatibility with Ag electrode. Meanwhile, negative zf can be tuned to near-zero (+3.7x10-6 degrees C-1) by adding CaTiO3 ceramic.

The temperature coefficient of the resonant frequency (tau(f)) of low-permittivity (epsilon(r)) microwave dielectric ceramics is required to be near 0 ppm/degrees C for practical application. However, owing to the polarization mechanism, tau(f) of low-epsilon(r) microwave dielectric ceramics is generally negative. Here, a novel microwave dielectric ceramic, Ba3-xSrxMgSi2O8, with an abnormal positive tau(f) at the applied temperature is presented. In this study, Sr2+ with a relatively small ionic radius was introduced to replace Ba2+, and a single-phase solid solution was formed (x > 0.5). Ba3-xSrxMgSi2O8 ceramics were discussed in glaserite-type topology with space groups of P33 for x <= 0.5, relatively high symmetry P33m1 for 0.5 < x < 2.5, and C2 for x >= 2.5. The epsilon(r) peaks as a function of temperature initially shift to low temperatures and then return to high temperatures through an ion substitution strategy. Notably, remarkable microwave dielectric properties for BaSr2MgSi2O8 were observed: epsilon(r) approximate to 14.2, Qxf approximate to 38,900 GHz, and tau(f) approximate to +117 ppm/degrees C, which are superior to those of other low-epsilon(r) silicate ceramics with positive tau(f) values. Density functional theory simulation calculations revealed that the preferential occupation of Sr2+ ions could decrease the intrinsic formation energy and improve the microwave dielectric properties by mitigating the ionic size mismatch within the crystal structure. The present research offers a strategy for discovering novel microwave dielectric ceramics with abnormal tau(f) values, which could serve as tau(f) regulators in practical applications because of their low cost and excellent microwave dielectric properties.

A novel BaMgSi4O10 ceramic was fabricated using a conventional solid-state method. The BaMgSi4O10 accompanied with BaMgSiO5, Ba2MgSi2O7, and SiO2 was detected for all compositions. Furthermore, microwave dielectric properties with εr = 5.7, Q × f = 17,900 GHz, and τf = − 19.1 ppm/°C were obtained at 1100 °C. To meet the requirement of LTCC technology, the optimum temperature can be lower than 850 °C by composing with 2 wt

The phase stability and dielectric behavior of the (1-x)(Sr-0.Na-6(0).La-2(0).Ti-2(0).Al-9(0).Nb-05(0).O-05(3))-xNdAlO(3) ceramic system (0.0 <= x <= 0.5) were systematically studied and optimized through tailored ionic substitution and a conventional single-step solid-state synthesis route. This strategy enabled synergistic enhancement by modifying lattice distortions and phonon dynamics, improving microwave performance of dielectric resonator antennas for potential applications in the C-band frequency range. X-ray diffraction confirmed a stable tetragonal (P4/mmm) phase for 0.0 <= x <= 0.5, with no secondary phases detected. Rietveld refinement and HRTEM validated solid solution formation, revealing lattice contraction and unit cell volume reduction with increasing x. Raman spectroscopy highlighted phonon modifications due to ionic substitutions. The microwave dielectric properties varied systematically, with epsilon(r) decreasing from 215 at x = 0.0 to 36.2 at x = 0.5 due to reduced ionic polarizability. The quality factor (Q x f) reached a maximum of 37,037 GHz at x = 0.4 due to increased atomic packing and minimized phonon scattering. The thermal coefficient of resonance frequency (tau(f)) was adjusted from 256 ppm/degrees C (at x = 0.0) to -12 ppm/degrees C (at x = 0.5), achieving enhanced thermal stability. The tetragonal phase at x = 0.4 demonstrated outstanding microwave dielectric characteristics, featuring an epsilon r of approximately 42, a Q x f value reaching 37,037 GHz, and a tau(f) of around -5 ppm/degrees C. These insights establish a clear structure-property relationship, paving the way for the development of high-performance microwave resonators.

In the present study, Sr1-xCaxAl12O19 (0 <= x <= 1.0) ceramics were fabricated via a solid-state reaction process at 1600 degrees C for 10 h. A systematic investigation was conducted to elucidate the correlation between calcium (Ca2+) substitution concentration and phase composition evolution, microwave dielectric properties and mechanical strength parameters. A new idea was proposed to resolve discrepancies in the evolution trends of the microwave dielectric characteristics between the Clausius-Mossotti theoretical predictions and the measured values according to the unique multilayer structure of magnetoplumbite. The optimum dielectric properties and bending strength were achieved at the full Ca2+ substitution level (x = 1.0): epsilon r = 14.4, Q x f = 9780 GHz, tau f = +210 ppm/ degrees C and sigma f = 254 MPa. By mixing Al2O3 with CaAl12O19, composite ceramics achieved concurrent near-zero tau f (+1.46 ppm/degrees C), high bending strength (sigma f= 376 MPa) with epsilon r of 11.1 and Q x f of 27,660 GHz, demonstrating promising HTCC applicability.

The shrinkage rate of Ni0.6Zn0.4Fe1.8O4 (NZF) ferrite was controlled to enable cofiring with BaTiO3 (BTO) at 1250 °C, forming BTO-NZF laminated structures. Postcofiring microstructural analysis revealed a well-bonded interface with minimal elemental interdiffusion. Notably, Ti4+ exhibited the highest diffusion coefficient (1.60 ± 0.05 × 10-12 cm2/s). Unidentified phases on the NZF side effectively restricted Ba2+ and Ti4+ diffusion. The BTO-NZF heterojunction consisted primarily of nanoscale amorphous layers containing Ba2+ and coherent crystalline regions. The dense amorphous barrier layer not only ensured strong interfacial bonding but also significantly suppressed interdiffusion. High-quality heterojunction formation was influenced by four primary factors, including the presence of similar ionic radii and interplanar spacings, amorphous barrier layers, and a certain concentration of large-radius ions. Magnetic characterization showed that NZF had a saturation magnetization (Ms) of 70.29 ± 0.50 emu/g, a coercivity (Hc) of 8.89 ± 0.50 Oe, and a remanent magnetization (Mr) of 1.01 emu/g. The relative dielectric constant (εr) of BTO ranged from 1490 to 2500 (at 1 MHz), while the dielectric loss tangent (tanδ) varied between 4 × 10-3 and 1.25 × 10-2. These findings offer valuable guidance for selecting cofired laminated substrates and designing high-performance heterojunctions. Moreover, the resulting cofired laminates exhibit excellent electromagnetic properties, demonstrating strong potential for magnetoelectric coupling applications.

A series of (Sr6-xCax)Ti2Nb8O30 (x = 0, 0.1, 0.3, 0.5, 1.0, 2.0) solid solutions were synthesized using a conventional solid-state method, and the effects of different Ca2 + doping amounts on the crystal structure and dielectric properties of the (Sr6-xCax)Ti2Nb8O30 ceramics were systematically studied. The results showed that the ceramics exhibited a tetragonal phase under all x values, and the lattice constant of the (Sr6-xCax)Ti2Nb8O30 ceramics decreased gradually as x increased. When x = 0, the relaxation dielectric peak appeared near - 75 degrees C in the ceramic samples, accompanied by a frequency-dispersion characteristic of relaxation ferroelectrics. In contrast, for other x values, the dielectric peak appeared near 150 degrees C and took on a rightward shift trend as x increased. At x = 1.0, the peak broadened, whereas at x = 2.0, a division peak appeared. This division may have resulted from the transition between paraelectric-ferroelectric and ferroelectric-ferroelastic states. In addition, the (Sr6-xCax)Ti2Nb8O30 ceramics exhibited a high relative permittivity (epsilon r approximate to 700) and low loss (tan delta approximate to 0.05) at x = 0.3, and the relative permittivity had a wide range of temperature stability from - 100 degrees C to 50 degrees C. The findings provide new research directions for the design and application of materials in chip ceramic capacitors.

Chiral metamaterials based on mirror-symmetry broken resonators are engineered to achieve a strong interaction with circularly polarized (CP) waves. However, in contrast to the widely-observed enhanced circular dichroism (CD), moderate/narrow-band optical activity (OA) responses are usually seen in chiral metadevices. Here, by engineering the chirality parameter that determines the effective refractive indices associated with the two CP eigenstates, a three-dimensional (3D) metamaterial consisting of 3D-printed ceramic meta-atoms exhibiting broadband strong OA with nondispersive near-zero ellipticity in the millimeter-wave regime is demonstrated. With four-fold rotational symmetry (C-4), the 3D dielectric metamaterial shows near-identical co-polarized transmission magnitude but distinct phase retardations under left-handed circularly polarized (LCP) and right-handed circularly polarized (RCP) illumination over a broad frequency range. Field analysis indicates that the observed OA behavior originates from the handedness-dependent light-matter interaction between the chiral meta-atoms and CP waves. Furthermore, large transmission CD and CP polarization conversion are observed in a metamaterial with C-2-symmetry, demonstrating the proposed systems' versatility in CP wave control. As revealed by the present study, coherently exploring the complex parametric space offered by 3D meta-atoms based on state-of-the-art 3D fabrication techniques can become a promising paradigm for engineering metamaterials with sophisticated functionalities.

Ca-substituted Ba1-xCaxMg2Al6Si9O30 ceramics were prepared to explore the relationships among their crystal structural parameters, phase compositions, dielectric properties, and coefficients of thermal expansion and applications in C-band antenna. The maximum solubility of Ba1-xCaxMg2Al6Si9O30 was located at x = 0.25, and Ba1-xCaxMg2Al6Si9O30 ceramics (0 <= x <= 0.25) crystallized in the space group P6/mcc. In Ba1-xCaxMg2Al6Si9O30 single-phase ceramics, epsilon(r) was dominated by ionic polarizability and "rattling effects" of Ba2+ and Al(2)(3+); Q x f was controlled by the roundness of [Si4Al2O18] inner rings and total lattice energy; and tau(f) was affected by the bond valence of Si/Al(1)-O(1). Notably, the low average coefficients of thermal expansion (2.668 ppm/degrees C) at -150 degrees C <= T <= 850 degrees C and near-zero coefficients of thermal expansion (1.254 ppm/degrees C) at -150 degrees C <= T <= 260 degrees C were achieved for the Ba1-xCaxMg2Al6Si9O30 (x = 0.1) ceramic. Optimum microwave and terahertz dielectric properties were obtained for the Ba1-xCaxMg2Al6Si9O30 (x = 0.1) ceramic with epsilon(r) = 5.80, Q x f = 31,174 at 13.99 GHz, tau(f) = -7.10 ppm/degrees C, and epsilon(r) = 5.71-5.85 at 0.2 THz <= f <= 1.0 THz. Also, the Ba1-xCaxMg2Al6Si9O30 (x = 0.1) ceramic substrate had been designed as a C-band patch antenna with a high simulated radiation efficiency (87.76%) and gain (6.30 dBi) at 7.70 GHz (|S-11| = -38.41 dB).

Novel Ba2RE2Si4O13 2 RE 2 Si 4 O 13 (RE RE = La, Nd, Sm, Eu, Gd, Ho, Er and Yb) ceramics were prepared by traditional solid reaction methods. The phase compositions of Ba2RE2Si4O13 2 RE 2 Si 4 O 13 ceramics were explored. The triclinic structure with P 1 space group of Ba2RE2Si4O13 2 RE 2 Si 4 O 13 ceramics was confirmed by TEM and Rietveld refinement analyses, and the decrease in the ionic radius of RE 3+ induced the phase transition from low symmetry (triclinic) to high symmetry (monoclinic) between Ba2Sm2Si4O13 2 Sm 2 Si 4 O 13 and Ba2Eu2Si4O13. 2 Eu 2 Si 4 O 13 . epsilon r-exp of the Ba2RE2Si4O13 2 RE 2 Si 4 O 13 ceramics was significantly affected by ionic polarisability. The 'rattling and compressing effects' of cations also affected the epsilon r-exp of Ba2RE2Si4O13 2 RE 2 Si 4 O 13 ceramics. The intrinsic dielectric loss of Ba2RE2Si4O13 2 RE 2 Si 4 O 13 ceramics were evaluated by the far-IR reflectivity spectrum, and high Q x f values of the Ba2Nd2Si4O13 2 Nd 2 Si 4 O 13 and Ba2Eu2Si4O13 2 Eu 2 Si 4 O 13 ceramics were attributed to their large total lattice energy and activation energy. The average bond valence of RE 3+ played an important role in controlling the tau fvalues f values of the Ba2RE2Si4O13 2 RE 2 Si 4 O 13 single-phase ceramics, and the high average bond valence of RE 3+ corresponded with the small negative tau f f values. Great microwave dielectric properties (epsilon r r = 11.52, Q x f = 33,600 GHz at 11.80 GHz and tau f f = -25.6 ppm/ degrees C) were obtained in the Ba2Nd2Si4O13 2 Nd 2 Si 4 O 13 single-phase ceramic.

The Ba(1-x)SrxCu(2)Ge(2)O(7) was successfully obtained through the solid-state reaction method, with single -phase BaCu2Ge2O7 formed at 850 degrees C. Scanning electron microscopy analysis revealed the excellent chemical compatibility of Ba(1-x)SrxCu(2)Ge(2)O(7) with silver. The properties of Ba(1-x)SrxCu(2)Ge(2)O(7) ceramics were explained using the P -V -L theory. The e(r-corr )decreased with the polarization rate (Sigma N-u*(chi)b(u)) and ion polarization of the unit cell. The Qxf increased with the chemical bond strength and lattice energy (Ucal), particularly the lattice energy of the Ge -O bond (U(Ge-O)). The af exhibited an opposite trend to the Qxf value and was influenced by the U(CuO) and susceptibility of the Cu -O bond (chi(Cu-O)). Sintering at 875( degrees)C for 3 h yielded optimal microwave dielectric performance for Ba1-xSrxCu2Ge2O7 ceramics, with observed values of epsilon(r) = 9.26 +/- 0.14, Qxf = 85,660 +/- 4200 GHz, and tau(f )= -15.6 +/- 1.1 ppm/C-degrees at x = 0.10. These promising microwave dielectric properties make Ba(1-x)SrxCu(2)Ge(2)O(7) a potential candidate for LTCC material applications.