微带线耦合介质谐振器的负载、空载及外界品质因数的确定

对微带线耦合介质谐振器来说,直接在谐振频率上测量反射系数或传播系数来确定空载、有载及外界品质因数。文中导出了其关系式并在相应的矢量面和标量面上作了阐述。同时介绍了线性频率换算图以及根据有载Q值的测试结果来精确求解空载Q值的图解法。     

用谐振腔-截止波导技术测量介质谐振器的复介电常数

在TE01n模谐振腔的一个端面中央,开一圆孔,连接一根等直径、适当长度的截止波导,当截止波导中置入介质谐振器时,使含介质段对TE01模呈传输态。介质谐振器的前向波导段用于调节耦合强弱,足够长度的背向波导段则形成匹配电抗终端或置入金属场构成短路终端。这两种安排都能使置入介质谐振器前后的谐振腔产生相当大的谐振长度和Q因子的变化,从而能获得准确的介质谐振器无载Q因子和介电常数。在X频段对陶瓷谐振器进行测量,获得满意的结果。     

输入输出电容对孔耦合同轴滤波器性能的影响

为了提高滤波器的电性能,研究了孔耦合两腔介质同轴滤波器的调试技术.理论上分析了耦合谐振器的频率和有载品质因数(Q)值与输入、输出电容的关系.采用介电常数εr=74的微波介质陶瓷制作了孔耦合两腔介质滤波器,通过观察反射系数(S11)波形讨论了输入、输出电容对滤波器性能的影响.结果表明,反射系数的波形和大小能直接反映出输入、输出电容的大小是否合适.最后制作出中心频率为902 MHz、通带带宽13.2 MHz、阻带衰减(f0士40 MHz)＞24.9 dB的带通滤波器.该调试技术对两腔以上介质滤波器的调试具有指导作用.     

用谐振腔—截止波导技术测量介质谐振器的复介电常数

在TE01n模谐振腔的一个端面中央,开一圆孔,连接一根等直径、适当长度的截止波导,当截止波导中置入介质谐振器时,使含介质段对TE01模呈传输态。介质谐振器的前向波导段用于调节耦合强弱,足够长度的背向波导段则形成匹配电抗终端或入金属场构成短路终端。这两种安排都能使置介质谐振前后的谐振腔产生相当大的谐振长度和Q甸子的变化,从而能获得准确的介质谐振器无载Q因子和介电常数。在X频段对陶瓷谐振器进行测量,获得满意的结果。     

测量与微带线耦合的介质谐振器特性的自动化技术

本文提出了一种测量与微带线耦合的介质谐振器的谐振频率、有载品质因数和耦合因子的计算机自动控制技术。借助于网络分析仪,以频率为自变量测出该系统复传输系数。计算每一个频率点上的反射系数并进行幅值处理,获得谐振器的特性参数。Q值和耦合因子的误差大约是1％,谐振频率的误差是10~(-6)。     

介质谐振器在微带电路中无载Q值的测量

本文提出了一种用测量与计算相结合的确定谐振器无载Q_u值的方法。此法尤其适用与微带线相耦合的介质谐振器的Q_u值的确定。只要测出与微带线相耦合的介质谐振器的谐振频率f_0,f_0。上的驻波比ρ和半功率点带宽△f_0.7,即可用本文给出的公式计算出介质谐振器的无载Q_u值和耦合系数β。实测结果表明所得的结果相对误差在5％以内。     

存在干扰模式时的微波谐振器Q值计算方法北大核心CSCD

谐振法测量介质介电常数时需要计算谐振器的无载Q值。当微波谐振器的工作模式受干扰模式影响时,会导致无载Q值的计算出现偏差。文章针对这种情况提出了一种存在干扰模式时计算微波谐振器无载Q值的迭代算法。该方法基于所提出的反向叠加和同相叠加两种等效电路模型,以传输系数模值平方之差在所有频点的平方之和作为目标函数,采用尺度变换最速下降法进行迭代。将圆柱形金属谐振腔的高Q值TE011模作为工作模式、简并的低Q值TM111模作为干扰模式,通过仿真和实测对该方法进行了验证。实测结果表明,当干扰模式较强时,3 dB法计算的工作模式Q值偏离真值14%,而所提出的迭代法的计算结果偏离真值不到1%。     

交叉耦合介质谐振腔滤波器

论述了TE01模介质谐振腔滤波器的设计方法。主要分析了介质谐振腔的设计、谐振腔之间的耦合,包括电耦合与磁耦合的实现。为了使TE01模滤波器与其它高Q值的滤波器具有可比性,采用交叉耦合来实现高性能滤波特性。仿真设计了一个6阶准椭圆函数滤波器,4个传输零点对称的分布在通带两侧,实现了较好的带外抑制。最后设计了一个同轴腔与介质谐振器混合耦合的滤波器,用来抑制介质滤波器寄生通带的影响。     

压电换能器电调介质滤波器的设计与实现

为了解决变容管电调窄带滤波器的插入损耗大和承受功率小的问题,研究了用压电换能器作电调元件的电调介质滤波器.分析了压电换能器调谐介质谐振器的机理,讨论了耦合系数和外部Q值的控制方法,仿真结果表明耦合系数和外部Q值随调谐频率的变化较小.采用HFSS软件设计和优化了两级电调介质滤波器的结构,并用高Q值的介质谐振器制作了两级电调介质滤波器.根据ANSYS软件的分析结果,提出了提高电调率的有效措施.当控制电压为0~50V时,滤波器的中心频率调谐范围为4.155~4.205GHz,3dB带宽为37~40MHz.     

采用介质谐振器和Q值极高的新型微波晶体管振荡器

本文介绍采用介质谐振器作匹配电路和频率确定元件的单端口与双端口微波晶体管振荡器,其外部Q值比介质谐振器的无载Q值大得多。文中还指出,上述双端口场效应管振荡器的可能用途是作自振荡式混频器。     

高阻带微波带通滤波器的研制

为了提高通信设备的性能,研制了高阻带的微波滤波器。该滤波器由5个高Q值的同轴介电陶瓷谐振器构成的带通滤波器。谐振器之间通过介电基片上的电容相互耦合。在装入外壳前,调整好每个谐振器的谐振频率和耦合电容,之后就不需要再调整,外壳上也没有可调零件,从而保证滤波器结构稳定,性能可靠。用εr=74的介电陶瓷制作出滤波器的性能为f0=982 MHz,Δf=10.9 MHzI,L=3.8 dB,阻带在f0±30 MHz处大于69 dB,远阻带衰减优于70 dB。     

2200 MHz圆环形介质谐振器的研制

讨论了TE011谐振模式的圆环形介质谐振器的研制过程。固定ZnO添加量为质量分数1.00%,考察了WO3改性剂对(Zr0.8Sn0.2)TiO4微波陶瓷介电性能的影响。当w(WO3)为0.25%时,可得到εr为38.0、Q值大于5800(7GHz)、τf小于2.0×10–6/℃的瓷料。以该瓷料为原料制作谐振器,研究了制作工艺和支撑物高度对谐振器性能的影响。发现采用冷等静压成型工艺所制谐振器的Q值比采用干压成型工艺提高了4%。获得了谐振频率为2200MHz的高Q值、高功率、高稳定性圆环形介质谐振器,完全满足设计要求。     

Improvement of the stopband spurious window for a dual-mode dielectric resonator filter by new coupling technique

This paper presents a new design technique for two configurations of a dual-mode filter using a dielectric loaded cavity operating at 1.95 GHz. The dielectric puck in the proposed filter was floated in the middle of a cylindrical metal cavity with short circuits on the side walls and holes through the ceramic from the side face. These holes allowed the insertion of coupling probes which did not affect the unloaded quality factor or the spurious window. The inline structure fourth pole Chebyshev dual mode filter offers a 870 MHz suppression window while the planar configuration was 710 MHz from the resonance frequency and the operation bandwidth of 54 MHz. The volume reduction ratio was eight times larger compared with a coaxial filter of the same Q factor.     

Microwave Bandpass Filters Containing High-Q Dielectric Resonators

This paper is concerned with dielectric disks used as resonators in microwave bandpass filters. For many years it has been known that modes of resonance occur in isolated dielectric bodies having air boundaries, and that very compact high-Q resonators can be achieved when /spl epsiv/ /sub r/, is high and tan /spl delta/ is low. High-purity TiO/sub 2/ ceramic material, for example, has an /spl epsiv/ /sub r/ about 100, tan /spl delta/ about 0.0001, and Q/sub u/ about 10 000. Practical applications of dielectric resonators have previously been limited by insufficient design information. Formulas are derived for the coupling coefficient between adjacent dielectric-disk resonators within a metal waveguide below cutoff. This metal enclosure is necessary for shielding and to prevent radiation loss. Comparisons between theoretical and experimental coupling coefficient values show very good agreement in each of the three bandpass configurations treated in this paper. Techniques of loop and probe coupling to the end resonators of a multiresonator bandpass filter are discussed and methods of supporting the resonators are suggested. The conclusion is made that microwave dielectric resonators offer important size reductions compared to conventional resonators of similar high Q, but that the center-frequency change of the dielectric resonators as a function of temperature is excessive for many applications. Temperature stabilization is one solution, but preferably a material should be developed having electrical characteristics similar to TiO/sub 2/ ceramic, but with at least an order of magnitude improvement in temperature sensitivity.     

厘米波段介质带通滤波器的设计与制作

为了提高基站的通信质量,研制了高性能的窄带介质带通滤波器。选择切比雪夫低通原型设计线路,采用6个环形介质谐振器直接耦合实现滤波器,输入输出采用探针耦合。用HFSS软件对滤波器的结构进行了仿真。用εr=38的高Q值介质陶瓷材料制作了环形谐振器,分析了衬垫材料的高度对环形谐振器性能的影响,测试了级间耦合系数。最后制作出中心频率为6GHz的介质带通滤波器,滤波器的带宽窄（0.5%）,插入损耗较小,阻带衰减很高,达到了国内先进水平。     

Rigorous analysis of shielded cylindrical dielectric resonators bydyadic Green's functions

This paper presents a rigorous approach for the calculation of resonant frequencies of a metallic cavity loaded by a dielectric resonator. Tangential fields at the air-dielectric interface are derived from dyadic Green's functions and boundary conditions are applied. Dyadic Green's identity and the boundary element method are used to solve the numerical problem. In order to validate the method, resonant frequencies are calculated for a cylindrical cavity loaded with a dielectric cylinder and compared with available results in the literature. Then resonance is studied for dielectric cylinder in a rectangular cavity. In the case of multiple dielectric resonators in the cavity, the coupling coefficient is computed with an original method based on the use of symmetries     

960 MHz同轴介质谐振器滤波器的研制

研制了用四个高Q值介质同轴谐振器构成的带通滤波器,谐振器之间的耦合通过陶瓷基片上的电容实现,讨论了影响谐振器插入损耗的主要因素。结果表明,该四级式低损耗介质同轴谐振器滤波器中心频率f0为960MHz,插入损耗小于3.0dB,能满足设计要求。     

Cavity coupling structure for planar oscillators showing DR-likereflective characteristics

A new cavity coupling structure has been developed for low-phase noise oscillator applications. Unlike the conventional cavity coupling structures that show absorption at the resonant frequency, the new structure shows high reflection at resonance similar to dielectric resonators, making it suitable for the reflective oscillators. The fabricated cavity resonator showed a loaded Q-factor of 1200 and the X-band oscillator using the new resonator showed phase noise proper-ties of -57 and -83 dBc/Hz at 1 and 10 kHz offset, respectively. This is comparable to the best results of dielectric resonator oscillators using HEMTs at this frequency range     

Compact bandpass filters for 800-MHz band land mobile radio equipments

Compact bandpass filters for 800-MHz land mobile radio equipment has been developed using coaxial resonators with a high dielectric constant material of εr= 35. The use of dielectric material of high Q and a dielectric substrate for coupling capacitors made possible the construction of compact low-insertion-loss filters. The performance characteristics of these filters are described.