Arbitrary Termination Impedances Research Articles

A Design Approach for Asymmetric Coupled Line Tandem Couplers With Arbitrary Terminal Real Impedances and Arbitrary Power Dividing Ratio

A Design Approach for Asymmetric Coupled Line Tandem Couplers With Arbitrary Terminal Real Impedances and Arbitrary Power Dividing Ratio

Substrate Integrated Waveguide Quasi-Elliptic Filter with Arbitrary Termination Impedances

This paper presents a quasi-elliptic filter (QEF) with arbitrary termination impedances (ATI). The proposed QEF is designed by adding cross-coupling between the first and last resonators of an ATI bandpass filter (BPF) with the Chebyshev response. The proposed QEFs with ATI can be designed in even-order resonators and the location of the pair transmission zeros (TZs) is controllable. To prove the validity of the proposed design, the fourth-order QEFs with ATI were implemented on a single-layer substrate-integrated waveguide (SIW) cavity at a center frequency (<i>f</i><sub>0</sub>) of 10 GHz with the pair TZs at 10 ± 1.4 GHz. These SIW QEFs with ATI improve frequency selectivity and effectively suppress the out-of-band signal with high power handling. The measured maximum insertion loss (|<i>S</i><sub>21</sub>|) and minimum return loss (|<i>S</i><sub>11</sub>|) of the SIW QEF with unequal real-to-real ATI are 0.93 dB and 17.4 dB, respectively, in the passband. Similarly, the maximum |<i>S</i><sub>21</sub>| and minimum |S<i>S</i><sub>11</sub>| of the SIW QEF with complex-to-real ATI are 1.2 dB and 18 dB, respectively.yer substrate-integrated waveguide (SIW) cavity at a center frequency (

Design of Compact Coupled-Line Complex Impedance Transformers With the Series Susceptance Component

In this brief, a compact coupled-line complex impedance transformer (CIT) with a series susceptance component is presented. It is composed of a coupled line and a susceptance component series at the edges of the coupled line. By inserting the susceptance component, arbitrary complex impedance can be transformed and the coupled line has weak coupling coefficient and small impedance value, which shows the feature of compact, easy fabrication and size miniaturization. The design equations for the proposed CIT are derived by using the port voltage-current method combined with the even-odd mode decomposition technology. For verification, two prototypes are designed at 1.0 GHz. The measured results demonstrate that good impedance matching is obtained by the proposed CIT with arbitrary terminal impedances.

A Simple and General Method for Filtering Power Divider With Frequency-Fixed and Frequency-Tunable Fully Canonical Filtering-Response Demonstrations

This paper proposes a general method to design the power divider (PD) with the arbitrary filtering response. The proposed model allows coupling matrix-based filter synthesis to be adopted in the Wilkinson PD (W-PD) design so that two-order, high-order, single-band, multiband, frequency-fixed, and frequency-tunable responses are all available for the W-PD. Meanwhile, benefiting from the generalized W-PD topology, the general model can be employed to design the PD with arbitrary termination impedances (TIs), arbitrary power division ratios (PDRs), and the highly favorable isolation. To demonstrate the proposed Wilkinson filtering PD (W-FPD), a series of resonator-coupled BPFs with open-end coupling feeding line and their corresponding coupling matrices are considered and applied to the W-FPD design. Accordingly, four frequency-fixed W-FPDs are designed to achieve four fully canonical responses with a full number of transmission zeros (TZs). In addition, two highly selective frequency-agile W-FPDs with the nearly constant absolute bandwidth (ABW) are designed to achieve the very wide frequency tuning range. The excellent simulation and measurement results experimentally validate that the proposed model can be utilized to realize W-FPD with two-order, high-order, single-band, multiband, equal, unequal, equal tunable, and unequal tunable filtering responses.

Balanced‐to‐unbalanced power dividers for arbitrary power division ratios and forarbitrary real termination impedances

Novel balanced-to-unbalanced power divider (BUPD) is introduced for arbitrary power division ratios and for arbitrary real termination impedances. It consists of one 180° transmission-line section (TL), two different 90° TLs and one isolation circuit comprising two different resistances and two different 90° TLs. Due to the arbitrary termination impedances, the conventional ways for the even- and odd-mode excitation analyses are impossible, requiring a new design method. Under the assumption of the perfect isolation between two output ports, the BUPD can be divided into two, based on which the design formulas for the characteristic impedances of all the TLs can be successfully derived. Then, the scattering parameters are inversely derived, which is quite different from the conventional ways where the design formulas are derived based on the scattering parameters. For the verification of the suggested theory, one prototype for the power division ratio of 5 dB and for the termination impedances of 60, 40 and 50 Ω is tested. The measured frequency responses are in good agreement with the predicted ones.

Unequal termination impedance parallel-coupled lines band-pass filter with arbitrary image impedance

This paper presents an analytical design for a microstrip parallel-coupled line bandpass filter (BPF) with arbitrary termination and image impedances. Using the proposed design formulas, multistage arbitrary termination impedance BPFs can be designed with a very high impedance transforming ratio (r). The fractional bandwidth and return losses are maintained even though the r and image impedance are varied. To validate the design formulas, two- and three-stage BPFs are fabricated and measure at the center frequency (f0) of 2.6 GHz. The filter 1 and filter 2 are designed with termination impedances of 50–300 Ω and 20–50 Ω, respectively. The measured results of both filters show a good agreement with the simulations. The measured passband insertion and return losses of filter 1 are better than 0.8 and 19.6 dB, respectively. Similarly, the measured passband insertion and return losses of filter 2 are better than 1.5 and 19 dB, respectively.

Field-to-Long-Segmented-Trace Coupling With Arbitrary Loads and a Transparent Upper Bound Using a Single Modified Taylor Cell

In modern electronic products, the printed circuit board (PCB) traces may well form the dominant coupling path in radiated immunity problems. Therefore, an understanding of the designable parameters that influences the worst-case induced voltages can be of use to the PCB designer, together with rapid simulations. Therefore, a modified single (unmeshed) Taylor cell is combined with the transmission line theory to predict the terminal voltages induced by a grazing, vertically polarized plane wave, incident on a multisegment trace with arbitrary terminal impedances. The resulting model is closed form and therefore suitable for rapid simulations. Furthermore, the model is geometrically approximated to provide understanding on how designable PCB parameters determine the worst-case induced voltage. Finally, the model is compared to measurement results.

3-dB Power Dividers With Equal Complex Termination Impedances and Design Methods for Controlling Isolation Circuits

<?Pub Dtl=""?> A 3-dB power divider (PD) terminated in equal complex impedances is presented. It consists of two identical 90 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">$^{\circ}$</tex></formula> transmission-line sections and an isolation circuit, being composed of resistance and capacitance, or resistance and inductance, depending on the termination impedances. If the termination impedance has capacitance, the isolation impedance should consist of inductance, and therefore, the isolation circuit should be implemented with a chip inductor. However, the chip inductor contains additional stray capacitance and resistance, which lead to undesired frequency performance. To avoid the usage of the chip inductors, even with arbitrary termination impedances, three design methods by adding transmission-line sections, adding open stubs, and adding short stubs are introduced. The PDs designed by the three methods can have not only desired isolation impedances, but also the total size of the PDs can be reduced. To verify the suggested theory, three PDs are measured. For one PD with adding transmission-line sections, the measured reflection coefficients at all ports are <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$-$</tex></formula> 43.29, <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$-$</tex></formula> 41.55, and <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">$-$</tex></formula> 51.69 dB, the isolation is 56.7 dB, and the power division is <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$-$</tex> </formula> 3.042 dB at a design center frequency of 1 GHz, which agree quite well with those predicted.

Analytical Design Method of Multiway Dual-Band Planar Power Dividers With Arbitrary Power Division

In this paper, a novel closed-form design method of generalized Wilkinson power dividers is proposed. By using this method, the power divider could be designed to be arbitrary-way (N-way) with arbitrary power division, and arbitrary dual-band operations in a pure planar structure. A previous dual-band unequal Wilkinson power divider is extended to arbitrary terminal impedances case, thus, it can be used to construct multiway planar power dividers through the combination of the two-section dual-frequency transformers. To obtain three-way (or any odd-way) power dividers with dual-band and unequal power division features, a new developed recombinant structure is employed. This recombinant structure consists of a two-way dual-band unequal power divider/combiner without any isolation structures. Furthermore, the complete design procedures and analytical equations of these proposed generalized power dividers are presented. To verify our proposed design approach in theory, several three-way and four-way power dividers with different dual-band applications and various power divisions are designed and simulated. Finally, a practical three-way power divider operating at both 0.6 and 2.45 GHz with a power dividing ratio of 3:5:1 is fabricated in microstrip technology as a typical example. The measured results of the fabricated power divider verify our proposed idea.

Toward Integrated Circuit Size Reduction

In this article, voltage-basis, current-basis, and normalized scattering matrices were introduced and it was shown that three different scattering matrices are the same only with equal termination impedances but only the normalized scattering matrix is correct with arbitrary termination impedances. The scattering matrices can be calculated from impedance, admittance, or ABCD matrices characterizing a network. However, if the network has more than three ports, the calculation process from the admittance or impedance matrices is not simple. For this, conversion formulas of the ABCD parameters into the normalized scattering parameters were presented for the impedance-transforming directional couplers. If one can have any choice of the termination impedances of the directional couplers as shown in this article, the total size of a microwave integrated circuit can be reduced.

임의의 종단 임피던스를 갖는 DC Block의 완전 정합

Design equations of DC blocks terminated in arbitrary impedances are newly suggested and a microstrip DC block is tested for the perfect matching. The DC block is a two-port passive component and the power excited at a port is transmitted into another port. However, all the excited power at the input can not be delivered to the output and therefore most of the conventional DC blocks can not be perfectly matched with arbitrary termination impedances. To solve the matching problem, its one-port equivalent resonant circuit model, from which design equations can be derived, is newly suggested. Using the derived design equations, any DC block can be designed, perfectly matched without any restriction of coupling coefficients. To verify the derived design equations, measurements were carried out and the results are in good agreement with prediction, showing insertion and return losses at 4.1 ㎓ are 0.82 ㏈ and －31 ㏈, respectively.

General design equations, small-sized impedance transformers, and their application to small-sized three-port 3-dB power dividers

In this paper, design equations for three-port power dividers have been derived. These design equations are available for both arbitrary power divisions and arbitrary termination impedances, and many sets of design equations are possible. Therefore, the design equations may be called general design equations and an arbitrary design impedance A is introduced to describe them. On the basis of the derived general design equations, a coplanar three-port power divider with a power split ratio (3 dB) terminated by 50, 60, and 70 /spl Omega/ is designed with A=33.33 /spl Omega/, so that a commercially available resistor 100 /spl Omega/ can be used for the isolation resistance. Additionally, to reduce the size of transmission-line impedance transformers, two types of small-sized impedance transformers are designed, named a constant VSWR-type transmission-line impedance transformer (CVT) and a constant conductance-type transmission-line impedance transformer (CCT) and compared with conventional reduced-sized impedance transformers. These impedance transformers are designed in the low-Q region on the Smith chart. Therefore, they show wide-band properties. To make sure that the derived design equations of CVTs and CCTs are reasonable, four 1;6:1 impedance transformers, CVT 20/spl deg/, CVT 30/spl deg/, CCT 15/spl deg/, and CCT 20/spl deg/ have been fabricated in microstrip technology and measured. The measured results show the expected tendency. Based on the CVTs and CCTs, small-sized three-port 3-dB power dividers are constructed and named a constant VSWR-type three-port 3-dB power divider (CVT3PD) and a constant conductance-type three-port 3-dB power divider (CCT3PD). For the CVT3PD and CCT3PD, perfect isolation conditions are derived, and it is shown that the perfect isolation circuit (I.C) must be composed of resistance combined with capacitance or inductance in the case that the length of transmission lines is not /spl lambda//4. These I.Cs are quite different from conventional ones composed of only resistance. Finally, on the basis of the derived perfect isolation impedance, CVT3PD and CCT3PD are designed and simulated, giving the possibility that a CCT3PD can be realized with the electrical length 15.30/spl deg/ of the transmission lines.

Arbitrary termination impedances, arbitrary power division, and small-sized ring hybrids

If a ring hybrid is terminated by arbitrary impedances, design equations cannot be derived with conventional methods because symmetry planes for even- and/or odd-mode excitation are not available. Therefore, under these conditions, new design equations for ring hybrids were derived. They can be applied to ring hybrids with both arbitrary termination impedances and arbitrary power-division ratios. Also, new design equations for small-sized ring hybrids have been developed. They allow the design of arbitrary power division, arbitrary termination impedances, and especially small-sized ring hybrids. On the basis of these derived equations, a theoretical evaluation was made using microstrip ring hybrids, and experiments are demonstrated using a coplanar ring hybrid.

WAVE PROPAGATION AND HARMONIC GENERATION IN TRANSMISSION LINES WITH PERIODIC NONLINEAR LOADS

ABSTRACT A general solution describing electromagnetic wave propagation alone a transmission line periodically loaded with varactor diodes, with arbitrary terminal impedances, is obtained up to 3rd order in the frame of the Volterra functional method. Forward phase-matched 2nd harmonic generation with matched generator and load impedances is treated in detail. Design curves are given.