General Field Theory Treatment of H-Plane Waveguide Junction Circulators

In this paper an exact field theory treatment for the waveguide junction circulators is presented. The treatment is general, being dependent on neither the geometrical symmetry of the junction nor the number of ports. The electromagnetic fields in the joining waveguides are written in the form of infinite summation of waveguide modes. The solutions of the wave equations in the ferrite rod and in the surrounding air are obtained in the form of infinite summation of cylindrical modes. The fields at the ferrite air interface and at an imaginary boundary chosen arbitrarily between the air region and the waveguides are then matched. This process leads to an infinite system of nonhomogeneous equations in the field amplitudes. Three types of waveguide junction circulators using this technique are analyzed: the simple ferrite-rod Y junction, the simple ferrite-rod T junction, and the latching Y junction. Point-matching techniques are used to get numerical results for the field distributions and the circulator characteristics. Excellent agreement has been found between the published experimental measurements and the numerical results obtained by this technique.     

Theoretical Design of Symmetrical Junction Stripline Circulators

The results of detailed calculations based on Bosma's theory of 3-port stripline circulators are presented. The analysis has been modified to enable the scattering matrix, and therefore the circulator bandwidth, to be found. The equations of the 4-port junction have been derived and an expression for the scattering matrix of the general m-port junction is given. A comparison of experimental and theoretical results for the 3-port junction shows good agreement for circulators designed in the frequency band 2-3 Gc. ,     

Computer-aided Design Of Stripline Ferrite Junction Circulators

A general design procedure is presented for stripline Y-junction circulators employing solid dielectric between ground planes. The resonator design and impedance matching are derived in a form suitable for computer evaluation. The procedure is applicable to cases where either the circulator bandwidth or the ground plane spacing is specified. An experimental S-band switching circulator illustrates the technique.     

Four-Port Crossed-Waveguide Junction Circulators

A detailed account is given of the experimental investigation which has led to the design of 4-port circulators at frequencies from 2.5 to 25 Gc. The complex behaviour of these devices is clarified by establishing the modes of circulation in any particular waveguide passband. The modes are defined in terms of the static magnetic field (H) required, the microwave frequency (f) and the direction of circulation. The shape of the mode characteristic depends upon the ferrite/brass configuration in the center of the junction and the mode charts are given for two possible ferrite arrangements. The fixed-field bandwidths of the two configurations are, respectively, 2-4 per cent and 4-8 per cent. The performances are: isolation (ports 1-4) >20 db, cross-coupling (ports 1-3) >20 db, VSWR <1.2 and insertion loss (ports 1-2), respectively, <0.5 db and <1.0 db for the two configurations. The tunable bandwidth depends upon the mode of circulation and varied from 5 to 15 per cent. The positions of the modes in the waveguide pass-band can be adjusted by changing the diameter of the center ferrite/brass post. This shifting of the center frequency is described in detail for both ferrite arrangements and, for particular modes of circulation, figures are given of the frequency shift per 0.001" change in ferrite and brass diameter.     

The Synthesis of Symmetrical Waveguide Circulators

A method for synthesizing symmetrical waveguide circulators by adjusting the eigenvalues of the scattering matrix is described. This procedure is particularly useful for the design of very compact circulators in the form of waveguide junctions containing ferrite obstacles. Permissible structural symmetries for a circulator are listed, and a standard form for the scattering matrix of a symmetrical circulator is defined. The synthesis procedure is then described in detail, stating the conditions to be imposed on the scattering matrix eigenvalues, and an expression is obtained for the changes in the eigenvalues due to the placing of anisotropic material within the junction. By applying the theory to Allen's 4-port turnstile circulator, it is shown that the use of a matched turnstile junction and a reflectionless Faraday rotator is not essential. The theory is also applied to the design of novel 3- and 4-port circulators, and two 6-port circulators, one of which may be used as a 5-position waveguide switch, are described. Some experimental results are presented for a compact 3-port circulator in the form of an H-plane Y junction, in 1 inch by 1/2 inch waveguide, containing a ferrite post obstacle. This circulator, which operates with a bias field of approximately 25 oersted, has a useful bandwidth of 3 per cent. Greater bandwidths would be expected in a Stripline or a fin-line version of this device.     

Design of Waveguide Circulators with Chebyshev Characteristics Using Partial-Height Ferrite Resonators

This paper outlines a step-by-step approach to the design of waveguide circulators using partial-height resonators, which incorporates every linear dimension of the device, The approach used consists of defining the physical variables of the ferrite region in terms of the frequency, VSWR, and bandwidth specification. It also incorporates the definition of the length and admittance level of the radial transformer. The model employed is essentially a two-mode one, with the third mode separately adjusted to exhibit an ideal electric-wall boundary condltion at the terminals of the junction.     

Design of Partial Height Ferrite Waveguide Circulators (Short Papers)

This short paper presents a design procedure for the widely used three-port waveguide circulator that has a partial height ferrite post in the junction region. Design formulas and curves are derived for two configurations of partial height circulators: one has a short circuit at one end of the ferrite post, while the other has dielectric spacers at both ends. The design method was used to build two circulators for operation at 38 GHz and 60 GHz, respectively. Excellent agreement between theory and experiment was obtained in predicting the center frequency and required matching structure of these devices.     

三角形结环行器中心频率的计算

本文给出了三角形结环行器中心频率的计算公式,并将理论结果与实验值进行了比较,两者相当一致。     

Ka波段波导对称五端口结设计

六端口反射计在微波网络测量方面具有很重要的地位,而对称五端口结则是构成六端口反射计的关键器件之一。介绍了一种工作于Ka波段的E面波导构成的对称五端口结。该五端口结采用中心多边形腔体外接标准波导的结构方式,并且采用加入介质柱以及电感性膜片的匹配方法。利用电磁仿真软件HFSS对其进行仿真优化,并对实物进行测量,证明所设计的对称五端口结性能良好,在整个Ka波段(26.5GHz～40GHz)各端口失配度均小于-16.8dB,可以很好地满足六端口系统的需要。     

8mm波导结环行器的仿真设计

介绍一种8mm波导结环行器的仿真设计方法,分析了环行器内部的电磁场,在仿真时采用了Ansofl Hfss和Ansofi Maxwell软件实现电磁联合仿真,有效的保证了仿真的准确性.在32.5GHz-36GHz频段,实测结果为驻波小于1.2,损耗小于0.4dB,隔离大于20dB.     

Computer-Aided Junctions Design of H-Plane Waveguide with Full-Height Ferrites of Arbitrary Shape

A method for solving the problem of H-plane waveguide junctions with a full-height ferrite post of arbitrary shape is proposed. The junctions are allowed to have arbitrary cross section and arbitrary number of ports. The method is based on the integral equations derived from the reciprocity theorems in both the ferrite region and the air region ranging from the reference planes of connecting waveguides to the inside of the junction. For comparison with the previously published experimental and theoretical results, Y junctions with a circular ferrite post are first treated. Excellent agreement has been found between the experimental data and the numerical results obtained by the present method. The performance of a Y-junction circulator with a triangular ferrite post having rounded angles is next investigated. Both the ferrite geometry and the internal dc magnetic field are examined in detail. For this geometry the calculated 20-dB bandwidth has been found to become greater as the cross section of the ferrite approaches a regular triangle from a circle.     

A General Equivalent Network of the Input Impedance of Symmetric Three-Port Circulators (Short Paper)

Starting from the network model of ferrite-filled resonators, a general equivalent network of the input impedance of symmetric, three-port circulators is given. The main advantage of the network, that it contains the original elements of the resonator model, so the physics of operation can be clearly seen and the results of field analysis can be directly used.     

A Flow Graph Analysis of 3--and 4-Port Junction Circulators

A simple theoretical model of a Iossless nonideal junction circulator is described. The model consists of a matched lossless n-port junction with a lossless two-port connected to each arm. The basic thought behind it is to separate the reflecting properties of the circulator from the other ones. For the case n=3, unsymmetrical as well as symmetrical junctions are treated. For a symmetrical three-port, the justification of the model has also been experimentally verified. In the case n=4, a symmetrical junction is treated. Flow graphs are used for visualizing the scattering matrices of combined networks and for calculating the coefficients of them.     

Reciprocal and Nonreciprocal Switches Utilizing Ferrite Junction Circulators (Correspondence)

The symmetrical ferrite junction circulator has assumed a position of prominence in recent years due to its small physical size and excellent electrical characteristics. The device was described theoretically by Auld, and other investigators have contributed to the design of improved electrical characteristics. Due to their low loss, these circulators have found wide use with parametric and tunnel diode amplifiers. Other applications include duplexers, multiplexer and load isolators.     

一种应用于电子战的双脊波导魔T接头

提出了一种可以应用于电子战的双脊波导魔 T 接头,介绍了它的基本原理,运用模式匹配和迭加的方法,对双脊波导魔 T 接头进行了分析和计算,设计了一种新型的双脊波导魔 T 接头.它不仅工作频带比标准波导魔 T 宽很多,而且结构尺寸大大减小,实现了宽频带功率分配器、合成器和射频电子开关的功能.实物测试的结果表明其性能良好.     

圆波导耦合TM01模旋转关节仿真设计

简单介绍了圆波导耦合TM01模旋转关节的基本原理、设计思路以及仿真方法。这种旋转关节的特点是能承受高脉冲功率,且旋转相位稳定,在承受大功率脉冲雷达馈线中是较为理想的旋转关节之一。依照本文的设计思路,可以方便、快速地确定旋转关节的尺寸,随后应用仿真软件对所设计的旋转关节进行电气性能上的优化,使其可以达到一个比较理想的电气性能指标。