Alignment and Adjustment of Synchronously Tuned Multiple-Resonant-Circuit Filters

Federal Telecommunication Laboratories, Inc., Nutley, N.J.
Proceedings of the IRE 12/1951; DOI: 10.1109/JRPROC.1951.273611
Source: IEEE Xplore

ABSTRACT A simple method of "tuning up" a multiple-resonant-circuit filter quickly and exactly is demonstrated. The method may be summarized as follows: Very loosely couple a detector to the first resonator of the filter; then, proceeding in consecutive order, tune all odd-numbered resonators for maximum detector output, and all even-numbered resonators for minimum detector output (always making sure that the resonator immediately following the one to be resonated is completely detuned). Also considered is the correct adjustment of the two other types of constants in a filter. Filter constants can always be reduced to only three fundamental types: f0, dr(1/Qr), and Kr(r+1). This is true whether a lumped-element 100-kc filter or a distributed-element 5,000-mc unit is being considered. dr is adjusted by considering the rth resonator as a single-tuned circuit (all other resonators completely detuned) and setting the bandwidth between the 3-db-down-points to the required value. Kr(r+1) is adjusted by considering the rth and (r+1)th adjacent resonators as a double-tuned circuit (all other resonators completely detuned) and setting the bandwidth between the resulting response peaks to the required value. Finally, all the required values for K and Q are given for an n-resonant-circuit filter that will produce the response (Vp/V)2=1 +(¿f/¿f3db)2n.

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    • "따라서 여파기의 적절한 초기 설계치가 필요하며 [3] , 또한, 초기 설계치가 얻어졌다고 하더라도, 최적화의 곤란 성으로 인해 이를 최적화할 적절한 방법이 필요하다. Swanson은 초기 설계 단계에서 과거 실험적으로 여파기 설계에 사용된 Dishal [5] "
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    ABSTRACT: In this paper, we present a design of a 5th order Chebyshev interdigital band-pass filter using inverter and susceptance slope parameter values obtained from EM simulated multi-port Y-parameters. The shifted length of the resonator is determined when the frequency of the transmission zero is separated far away from the center frequency. For the initial dimensions of the interdigital filter, the filter is decomposed into the individual resonators, and the dimensions are obtained using EM Simulation of the decomposed resonators. However, the interdigital filter with the dimensions determined from the EM simulation of the decomposed resonators shows slightly distorted response from the desired frequency response due to the coupling between non-adjacent resonators. To obtain a EM simulation dataset, EM simulation for this filter is carried out by parameter sweep with constant ratio for the initial values. In this dataset, it is determined the final values for the filter by optimization. The fabricated filter by PCB shows an upper-shift of center frequency of about 70 MHz, which was caused by permittivity changed and tolerance of fabrication.
    07/2011; 22(7). DOI:10.5515/KJKIEES.2011.22.7.694
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    • "Ideally , as in [2] and [10], all detuned resonators are completely short circuited to eliminate the loading effects entirely. A filter with a perfectly shorted resonator will not transmit any signal and, therefore, the techniques of [2] and [10] rely on the measurement of the reflected signal or . The measurement of the reflected signal requires the use of directional couplers that make integration more difficult. "
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    ABSTRACT: A system and method for the automated tuning of coupled resonator tunable filters is presented. The system and method are amenable to integration and are developed for on-board and on-chip automatic tuning of tunable filters without the use of a vector network analyzer and with minimal additional hardware. An analytical coupling matrix-based model of the tuning algorithm is developed to analyze and predict the performance of the tuning algorithm. The tuning model is verified with the automated tuning algorithm operating on a realized tunable filter. Finally, a low-cost hardware prototype for scalar transmission measurement for standalone implementation of the algorithm is also presented.
    IEEE Transactions on Microwave Theory and Techniques 01/2011; DOI:10.1109/TMTT.2010.2085791 · 2.94 Impact Factor
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    • "The design strategy adopted in this work is that developed by Swanson [14]. Swanson combined the concepts of Dishal [15], the EM simulation, and the port tuning method to outline a general and powerful procedure for a narrow-band multi-resonator filter design. Dishal's design method for narrow-band filters offers a very simple and intuitive approach that can be applied to different filter technologies and topologies. "
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    ABSTRACT: This paper appears in: Microwave, Antenna, Propagation and EMC Technologies for Wireless Communications, 2009 3rd IEEE International Symposium on Issue Date: 27-29 Oct. 2009 On page(s): 1019 - 1022 Location: Beijing Print ISBN: 978-1-4244-4076-4 INSPEC Accession Number: 11021857 Digital Object Identifier: 10.1109/MAPE.2009.5355854 Date of Current Version: 18 December 2009 Abstract A new compact microstrip bandpass filter design is presented in this paper as a candidate for use in modern wireless communication systems. The proposed filter structure is composed of two fractal-based microstrip resonators. The structure of each resonator is in the form of the 3rd iteration Peano fractal curve. The resulting filter structure based on these resonators, shows a considerable size reduction compared with the other microstrip bandpass filters based on other space-filling geometries designed at the same frequency. A second bandpass filter design based on the same resonator but with a tuning stub has been also presented, in an attempt to provide practically useful means to tune the filter to the specified performance with a considerable tuning range. The performance of the resulting filter structures has been evaluated using a method of moments (MoM) based electromagnetic simulator IE3D, from Zeland Software Inc. Results show that the proposed filter structures possess good return loss and transmission responses besides the size reduction gained, making them suitable for use in a wide variety of wireless communication applications. Furthermore, performance responses show that the second filter, based on Peano shaped resonator with stub, has less tendency to support the 2nd harmonic.
    2009 3rd IEEE International Symposium on Microwave, Antenna, Propagation and EMC Technologies for Wireless Communications (MAPE 2009); 01/2009
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