KR100332880B1 - Dielectric ceramic compositions having superior permittivity and low loss for microwave applications - Google Patents
Dielectric ceramic compositions having superior permittivity and low loss for microwave applications Download PDFInfo
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Abstract
본 발명은 듀플랙서 등의 부품에 사용되는 고주파 유전체 조성물에 관한 것으로, 그 목적은 15,000∼40,000의 Qf와 TCF를 자유롭게 조절하면서 유전율을 40수준으로 올릴 수 있는 고주파 유전체 조성물을 제공함에 있다.The present invention relates to a high frequency dielectric composition for use in parts such as duplexers, and its object is to provide a high frequency dielectric composition capable of raising the dielectric constant to 40 levels while freely adjusting the Qf and TCF of 15,000 to 40,000.
상기 목적을 달성하기 위한 본 발명은,The present invention for achieving the above object,
a ZrO2- b ZnO - c Nb2O5- d TiO2[ 5.0 ≤ a ≤45.0, 1.5 ≤b ≤18.0, 1.5 ≤c ≤18.0, 50.0 ≤d ≤59.0]로 조성되는 유전체 조성물; 그리고,a ZrO 2 -b ZnO -c Nb 2 O 5 -d TiO 2 [5.0 ≦ a ≦ 45.0, 1.5 ≦ b ≦ 18.0, 1.5 ≦ c ≦ 18.0, 50.0 ≦ d ≦ 59.0]; And,
a ZrO2- b ZnO - c Nb2O5- d TiO2[5.0 ≤ a ≤45.0, 1.5 ≤b ≤18.0, 1.5 ≤c ≤18.0, 50.0 ≤d ≤59.0]의 기본조성에a ZrO 2 -b ZnO-c Nb 2 O 5 -d TiO 2 [5.0 ≤ a ≤ 45.0, 1.5 ≤ b ≤ 18.0, 1.5 ≤ c ≤ 18.0, 50.0 ≤ d ≤ 59.0]
SnO2, MnO2, Ta2O5, CaO, SiO2, Sb2O5, Sb2O3, Al2O3, WO3의 그룹에서 선택된 1종 또는 2종이상과 MgO:1.5wt%이하로 조성되는 저손실 고유전율 고주파 유전체 조성물에 관한 것을 그 기술적요지로 한다.One or more selected from the group of SnO 2 , MnO 2 , Ta 2 O 5 , CaO, SiO 2 , Sb 2 O 5 , Sb 2 O 3 , Al 2 O 3 , WO 3 and MgO: 1.5wt% or less The technical gist of the low loss high dielectric constant high frequency dielectric composition constituted by
Description
본 발명은 듀플랙서 등의 부품에 사용되는 고주파 유전체 조성물에 관한 것으로, 보다 상세하게는 유전율 40 수준에서 높은 품질계수(Qf)를 가지면서 공진주파수의 온도계수를 안정하게 조절할 수 있는 고주파 유전체 조성물에 관한 것이다.The present invention relates to a high frequency dielectric composition for use in parts such as duplexers, and more particularly, a high frequency dielectric composition capable of stably adjusting the temperature coefficient of the resonance frequency while having a high quality factor (Qf) at a dielectric constant of 40. It is about.
최근 이동통신 등과 같은 고주파 통신의 발달에 따라 고주파신호를 대역 필터링하는 유전체세라믹이 듀플랙스, 대역통과 필터, 공진기 등의 부품으로 널리 사용되고 있다. 유전체세라믹에는 유전율(k), 품질계수(Qf), 공진주파수의 온도계수가 가장 중요한 항목이다.Recently, according to the development of high frequency communication such as mobile communication, dielectric ceramics for band filtering high frequency signals are widely used as components of duplex, band pass filter, resonator, and the like. Dielectric constant (k), quality factor (Qf), and temperature coefficient of resonant frequency are the most important items in dielectric ceramic.
(1) 유전율(1) permittivity
이동통신 단말기에 사용되는 공진기, 필터, 듀플랙서 등은 유전체 세라믹으로 제조되는데, 이들 세라믹부품의 크기는 유전체 세라믹의 유전율 크기에 반비례한다. 따라서, 단말기의 소형화를 위해서는 유전율이 큰 유전체 조성물이 요구된다.Resonators, filters, duplexers and the like used in mobile communication terminals are made of dielectric ceramics. The size of these ceramic components is inversely proportional to the dielectric constant of the dielectric ceramics. Therefore, in order to miniaturize the terminal, a dielectric composition having a high dielectric constant is required.
[관계식 1][Relationship 1]
(여기서, L은 유전체 필터의 길이, k 는 유전율)Where L is the length of the dielectric filter and k is the permittivity.
(2) 품질계수(이하, 'Qf'로 표기)(2) Quality factor (hereinafter referred to as 'Qf')
유전체필터의 주파수 선택성(selectivity)은 유전손실이 작아야 좋아진다. 즉, 유전손실(tanδ)의 역수인 Q값이 커야 하며 제품기종에 따라 일정 Q값 이상이 필요하게 된다.The frequency selectivity of the dielectric filter is improved when the dielectric loss is small. That is, the Q value, which is the inverse of the dielectric loss tanδ, must be large, and a certain Q value or more is required depending on the product model.
(3)공진주파수의 온도계수(이하, 'TCF'로 표기)(3) Temperature coefficient of resonant frequency (hereinafter referred to as 'TCF')
일정주파수에서 위상각이 "0"이 되어 전송로 R,G 만이 존재하는 시점이 있는데, 이 지점을 공진점이라 하고 이때의 주파수를 공진주파수라 한다. 이 공진주파수의 온도안정성을 위해서는 TCF가 0에 가까울수록 유리하다.At a certain frequency, the phase angle becomes "0" and there are times when only transmission paths R and G exist. This point is called a resonance point and the frequency is called a resonance frequency. For the temperature stability of this resonant frequency, the closer the TCF is to 0, the better.
이외에도 공진기를 만들 경우에 전극과의 밀착력 그리고, 전극도포후 공진기의 품질계수(Qf)의 향상을 위해 재료자체가 균일하고 미세한 조직을 갖는 것이 요구되고 있다.In addition, when the resonator is made, it is required to have a uniform and fine structure of the material itself in order to improve the adhesion between the electrode and the quality factor Qf of the resonator after electrode application.
미국특허공보 5,198,396(1993. 5. 30)호에는 유전율 30수준의 유전체 조성물이 제시되어 있다. 이 유전체 조성물은 BaO-xTiO2[3.7≤x≤4.5]의 기본조성에 1.0∼10wt%의 Ba3Ti12Zn7O34와 2∼8wt%의 Ta2O5가 첨가되어 조성되며, 4.5GHz에서의 Q값이 8000이상이고 공진주파수의 온도안정계수가 -16∼+12ppm/℃의 특성을 갖는다. 이 조성물은 유전율이 최고 39로서 첨가제와 조성변화로도 유전율 향상에 한계가 있어 새로운 크기 및 기종의 듀플렉서 등의 전자제품에 적용하기 힘든 문제점이 있다.U.S. Patent No. 5,198,396 (May 30, 1993) discloses a dielectric composition having a dielectric constant of 30 levels. This dielectric composition is composed of BaO-xTiO 2 [3.7≤x≤4.5] added with 1.0-10 wt% Ba 3 Ti 12 Zn 7 O 34 and 2-8 wt% Ta 2 O 5 added thereto, 4.5GHz Has a Q-value of 8000 or more and a temperature stability coefficient of resonance frequency of -16 to +12 ppm / ° C. Since the composition has a dielectric constant of 39, there is a limitation in improving the dielectric constant even with additives and composition changes, which makes it difficult to apply to electronic products such as duplexers of new sizes and models.
또한, 유전율 30수준으로 ZrO2-TiO2계에 소결성향상을 위해 SnO2, NiO를 첨가한 유전체 조성물이 알려져 있으나, 여전히 소결온도가 1400℃로 높은 실정이다.In addition, a dielectric composition containing SnO 2 and NiO added to ZrO 2 -TiO 2 system to improve sintering property at a dielectric constant of 30 is known, but the sintering temperature is still high at 1400 ° C.
이와 같이 유전율 30수준에서 Qf와 TCF를 적정수준을 확보한 조성물은 여러 가지 있으나, Qf와 TCF를 떨어뜨리지 않으면서 유전율을 40수준으로 향상시킨 유전체 조성물은 얻지 못하고 있는 실정이다.As described above, there are many compositions that have an adequate level of Qf and TCF at the dielectric constant of 30, but a dielectric composition having improved dielectric constant of 40 without dropping Qf and TCF has not been obtained.
본 발명은 15,000∼40,000의 Qf와 TCF를 안정적으로 조절하면서 유전율을 40수준으로 올릴 수 있는 고주파 유전체 조성물을 제공하는데 그 목적이 있다.An object of the present invention is to provide a high frequency dielectric composition capable of raising the dielectric constant to 40 levels while stably adjusting the Qf and TCF of 15,000 to 40,000.
상기 목적을 달성하기 위한 본 발명의 고주파 유전체 조성물은,The high frequency dielectric composition of the present invention for achieving the above object,
a ZrO2- b ZnO - c Nb2O5- d TiO2[ 5.0 ≤ a ≤45.0, 1.5 ≤b ≤18.0, 1.5 ≤c ≤18.0, 50.0 ≤d ≤59.0]로 조성된다.a ZrO 2 -b ZnO -c Nb 2 O 5 -d TiO 2 [5.0 ≦ a ≦ 45.0, 1.5 ≦ b ≦ 18.0, 1.5 ≦ c ≦ 18.0, 50.0 ≦ d ≦ 59.0].
또한, 본 발명의 유전체 조성물은, a ZrO2- b ZnO - c Nb2O5- d TiO2[5.0 ≤ a ≤45.0, 1.5 ≤b ≤18.0, 1.5 ≤c ≤18.0, 50.0 ≤d ≤59.0]의 기본조성에; MgO, SnO2, MnO2, Ta2O5, CaO, SiO2, Sb2O5, Sb2O3, Al2O3, WO3의 그룹에서 선택된 1종이상:1.5%이하로 조성된다.In addition, the dielectric composition of the present invention, a ZrO 2 -b ZnO-c Nb 2 O 5 -d TiO 2 [5.0 ≤ a ≤ 45.0, 1.5 ≤ b ≤ 18.0, 1.5 ≤ c ≤ 18.0, 50.0 ≤ d ≤ 59.0] On the basic composition of; At least one selected from the group consisting of MgO, SnO 2 , MnO 2 , Ta 2 O 5 , CaO, SiO 2 , Sb 2 O 5 , Sb 2 O 3 , Al 2 O 3 , and WO 3 : 1.5% or less.
이하, 본 발명을 상세히 설명한다.Hereinafter, the present invention will be described in detail.
본 발명은 ZrO2-TiO2계에서 소결성이 나쁜 ZrO2대신 ZnO, Nb2O5를 일부 치환하여 고주파 유전특성을 제어하면서 소결성을 향상하는데, 그 특징이 있다. 또한, ZrO2-ZnO-Nb2O5-TiO2계에 MgO, SnO2, MnO2, Ta2O5, CaO, SiO2, Sb2O5, Sb2O3, Al2O3, WO3를 첨가하여 유전율, Qf의 특성을 향상하는데도 특징이 있다.The present invention improves the sinterability while controlling high frequency dielectric properties by partially replacing ZnO and Nb 2 O 5 in place of ZrO 2 having poor sinterability in the ZrO 2 -TiO 2 system. In addition, in the ZrO 2 -ZnO-Nb 2 O 5 -TiO 2 system, MgO, SnO 2 , MnO 2 , Ta 2 O 5 , CaO, SiO 2 , Sb 2 O 5 , Sb 2 O 3 , Al 2 O 3 , WO It is also characterized by the addition of 3 to improve the dielectric constant and Qf characteristics.
본 발명의 ZrO2-ZnO-Nb2O5-TiO2계 조성물에서 ZrO2를 5∼45mol%로 하면서 ZnO와 Nb2O5를 각각 1.5∼18mol%로 하는데, 이는 ZnO와 Nb2O5의 양이 많아질수록 유전율은 증가하고, TCF는 음에서 양의 방향으로 증가하는 경향을 나타내며 소결밀도 역시 1.5mol%이상에서 높은 소결밀도를 얻을 수 있다. ZnO와 Nb2O5의 양이 18mol%를 넘을때에는 다시 소결밀도가 감소하기 때문이다.While in the ZrO 2 -ZnO-Nb 2 O 5 -TiO 2 based composition of the invention, the ZrO 2 in 5~45mol% in the ZnO and Nb 2 O 5 each in 1.5~18mol%, that of ZnO and Nb 2 O 5 As the amount increases, the dielectric constant increases, and TCF tends to increase in the negative to positive direction, and a high sintered density of 1.5 mol% or more can be obtained. This is because when the amount of ZnO and Nb 2 O 5 exceeds 18 mol%, the sintered density decreases again.
상기 ZrO2-ZnO-Nb2O5-TiO2계에 MgO, SnO2, MnO2, Ta2O5, CaO, SiO2, Sb2O5,Sb2O3, Al2O3, WO3를 첨가하여 유전율, Qf의 특성을 향상시키는데, 그 첨가량은 1.5wt%이하로 하는 것이 바람직하다. 그 이유는 이들의 첨가로 TCF의 큰 변화없이 Qf의 값을 향상시킬 수 있는데 그 첨가량이 1.5wt%를 넘으면 Qf값이 급격히 저하하기 때문이다.MgO, SnO 2 , MnO 2 , Ta 2 O 5 , CaO, SiO 2 , Sb 2 O 5 , Sb 2 O 3 , Al 2 O 3 , WO 3 in the ZrO 2 -ZnO-Nb 2 O 5 -TiO 2 system It is added to improve the dielectric constant, Qf characteristics, the addition amount is preferably 1.5wt% or less. The reason for this is that the addition of these can improve the value of Qf without a large change in TCF because the Qf value drops rapidly when the addition amount exceeds 1.5wt%.
이하, 본 발명을 실시예를 통하여 보다 구체적으로 설명한다.Hereinafter, the present invention will be described in more detail with reference to Examples.
[실시예]EXAMPLE
순도 99%이상의 ZrO2, ZnO, Nb2O5, TiO2, MgO, SnO2, MnO2, Ta2O5, CaO, SiO2, Sb2O5, Sb2O3, Al2O3, WO3를 표 1에 나타낸 조성비에 따라 칭량하여 순수(D.I water)를 용매로 하여 안정화 ZrO2볼을 사용하여 16시간 습식 혼합한 후 건조하였다. 건조한 분말은 1050℃에서 2시간 열처리하였다. 열처리한 분말을 다시 1시간 습식 분쇄한 후 건조하고, 건조된 분말에 3중량%의 결합제를 넣어 혼합한 후 60메쉬 체로 체가름하고 TE 모드로 측정하기 위해 14mm 몰드를 사용하여 1.5톤의 압력으로 일축성형 하였다. 소결은 1250∼1270℃ 사이에서 3시간 행하였다. 고주파 유전특성을 측정하기 위하여 지름:높이=1:0.45이상 되도록 거울면으로 연마한 후 평행도체판법(post resonant)을 사용하여 유전상수(k)와 품질계수(Qf)값을 측정하였다. 또한, 공진주파수의 온도계수(TCF)는 20∼80 사이에서 측정하였다. 이들 측정값을 아래 표 1에 나타내었다.Purity more than 99% ZrO 2 , ZnO, Nb 2 O 5 , TiO 2 , MgO, SnO 2 , MnO 2 , Ta 2 O 5 , CaO, SiO 2 , Sb 2 O 5 , Sb 2 O 3 , Al 2 O 3 , WO 3 was weighed according to the composition ratios shown in Table 1, followed by wet mixing for 16 hours using a stabilized ZrO 2 ball, using pure water (DI water) as a solvent, followed by drying. The dry powder was heat treated at 1050 ° C. for 2 hours. The heat-treated powder was wet-pulverized again for 1 hour, dried, and mixed with 3% by weight of a binder in a dried powder. Uniaxial molding was performed. Sintering was performed for 3 hours between 1250-1270 degreeC. In order to measure the high frequency dielectric characteristics, the dielectric constant (k) and the quality factor (Qf) were measured using a post-resonant after polishing with a mirror surface such that diameter: height = 1: 0.45 or more. In addition, the temperature coefficient (TCF) of the resonance frequency was measured between 20 and 80. These measurements are shown in Table 1 below.
표 1의 실험(1∼7)에서 알 수 있듯이, ZnO, Nb2O5의 함량이 증가하면 유전율과 Qf가 증가하고, 공진주파수의 온도계수는 음에서 양의 방향으로 증가하여 ZnO, Nb2O5의 함량이 약 10mol%에서 음에서 양으로 변하였다. 소결밀도도 ZnO, Nb2O5의 함량이 약 1.5이상 18.0mol%미만에서 4.8이상의 높은 소결밀도를 나타내었다.As can be seen from the experiments (1 to 7) of Table 1, when the contents of ZnO and Nb 2 O 5 are increased, the dielectric constant and Qf are increased, and the temperature coefficient of the resonance frequency is increased from negative to positive direction so that ZnO, Nb 2 The content of O 5 changed from negative to positive at about 10 mol%. The sintered density showed high sintered density of 4.8 or more at the content of ZnO and Nb 2 O 5 of about 1.5 or more and less than 18.0 mol%.
또한, 실험(5-1, 5-2, 5-3)는 실험5의 조성물에 MgO를 첨가한 것으로, MgO의 첨가에 따르는 고주파 유전특성의 변화를 살펴보면, MgO첨가시에 유전율과 Qf값은 증가하는데, MgO가 1.6% 첨가시에 Qf값은 급격히 감소하였다. MgO첨가에 따라 공진주파수의 온도계수의 조절도 가능하였다.In addition, experiments (5-1, 5-2, 5-3) are the addition of MgO to the composition of Experiment 5, the change in high-frequency dielectric properties with the addition of MgO, the dielectric constant and Qf value at the time of MgO addition When the MgO was added at 1.6%, the Qf value rapidly decreased. The addition of MgO also allowed adjustment of the temperature coefficient of the resonant frequency.
또한, 실험(5), 실험(4), 실험(3)의 조성물에 Ta2O5, WO3, Sb2O5, SnO2, CaO, Al2O3를 첨가하면 유전율의 큰 변화 없이 Qf값이 큰 폭으로 증가함을 알 수 있다. 공진주파수의 온도계수도 미세한 범위에서 조절이 가능하였다.In addition, when Ta 2 O 5 , WO 3 , Sb 2 O 5 , SnO 2 , CaO and Al 2 O 3 were added to the composition of Experiment (5), Experiment (4) and Experiment (3), Qf was not significantly changed. It can be seen that the value increases significantly. The temperature coefficient of the resonant frequency was also adjustable in a fine range.
상술한 바와 같이, 본 발명에 따르면 품질계수의 저하 없이 공진주파수의 온도계수를 자유롭게 조절하면서 유전율을 40수준으로 개선한 유전체 조성물이 제공되며, 이 유전체 조성물은 소결성도 향상되어 양산시에 수축률제어 및 유전상수 제어에 유리하고 공진주파수의 온도계수가 ±10ppm/℃의 범위내에서 품질계수가 30,000이상으로 유용한 효과가 있는 것이다.As described above, according to the present invention, there is provided a dielectric composition having improved dielectric constant to 40 levels while freely adjusting the temperature coefficient of the resonance frequency without degrading the quality coefficient. It is advantageous for constant control and has a useful effect of having a quality factor of 30,000 or more in the range of a temperature coefficient of resonant frequency of ± 10 ppm / ° C.
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