Filter Tuning Based on Linear Decomposition of Scattering Characteristics

Abstract

Abstract-This paper proposes a microwave filter post-production tuning based on an optimization process which finds the vector of deviations of tuning elements that should be applied to tune the filter. To build the system, the coarse set of scattering parameters is collected in such a way that every tuning element is detuned while other elements remain in their proper positions. In the concept, it is assumed that the relation between the positions of tuning elements and filter scattering characteristics can be modelled by the sum of one argument polynomial functions. Each polynomial function depends on the value of only one tuning element. Therefore, the measured filter characteristics can be linearly decomposed to characteristics from the collected coarse set and corresponding tuning element deviations can be found. This is done by way of optimization process. The presented numerical and physical experiments on the 7th order cross-coupled, bandpass filter have verified our approach.

Diagnosis of Coupled Resonator Bandpass Filters Using Vf and Optimization Method

“…Early filter diagnosis techniques can be traced back to the 1970s and 1980s [1,2]. In the past years, interest is growing on the filter diagnosis methods for extracting the coupling matrix of microwave filters from the measurements (or simulations) with losses [3][4][5][6][7][8][9][10][11][12][13][14][15]. These filter diagnosis or coupling matrix (CM) extraction techniques require two sorts: 1) CM extraction techniques are based on optimization (as in [3][4][5]) for matching the measured scattering parameters, whose elements are the problem unknowns.…”

“…In the past years, interest is growing on the filter diagnosis methods for extracting the coupling matrix of microwave filters from the measurements (or simulations) with losses [3][4][5][6][7][8][9][10][11][12][13][14][15]. These filter diagnosis or coupling matrix (CM) extraction techniques require two sorts: 1) CM extraction techniques are based on optimization (as in [3][4][5]) for matching the measured scattering parameters, whose elements are the problem unknowns. The optimization techniques are either greatly influenced by the initial values assigned to the variables, number of the resonators and topology of the filters, or are time consuming; and 2) CM extraction techniques are based on a polynomial model, which matches the measured (or the simulated) parameters and then extract the CM of the filter with a specified topology (by using well-known established methods as in [16]).…”

A Hybrid Computer-Aided Tuning Method for Microwave Filters

“…4) Another diagnosis techniques are based on optimization, such as [21][22][23][24][25][26][27][28][29][30]. The optimization procedures are either time consuming (for global optimization) or are sensitive to the initial value and the number of variables.…”

“…Since the traditional tuning process is nontrivial, time consuming and very expensive, a great deal of efforts have been made on computer-aided tuning (CAT) on microwave coupled resonator filters in recent years [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30].…”

A Fast Tuning Method for Microwave Filter Using Vf-Asm Technology

“…For a de-tuned filter, the corresponding characteristic filter parameters can be extracted from S-parameter measurement through many techniques, such as Cauchy method [4][5][6]. Recently a great deal of effort has been made on computer aided tuning for microwave filter [7][8][9][10][11][12][13][14][15][16][17][18][19][20]. In this paper, a novel hybrid method are proposed.…”