Design and implementation of inverse legendre microstrip filter

Abstract

The inverse Legendre filter response is derived and its property is analysed by providing the magnitude specifications in the passband and stopband. The inverse Legendre function requires the identical order n as its Legendre counterpart. A quantitative comparison is carried out between Chebyshev, inverse Chebyshev, Legendre and inverse Legendre to show the improved characteristics of the inverse Legendre filters depending on specifications and criteria. The inverse Legendre filter shows maximally flat characteristic in the passband and in comparison to other filters, it exhibits improved group delay characteristics. Finally, the filter is implemented in microstrip low pass configuration and a prototype model of the proposed filter configuration is developed and measured. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:69–73, 2017

Design and Fabrication of Compact Microstrip Low-pass Filter with Thin Film Technique for Wideband Applications

“…Thin film microstrip filters have been studied before in different frequency bands [12][13][14][15][16][17], and successful results are obtained in these studies. In [12], the design and fabrication of a microstrip band-pass filter based on quadruplet geometry is reported, where the filter resembles elliptic function near passband and Chebyshev filter in the stopband.…”

“…Thin film microstrip filters have been studied before in different frequency bands [12][13][14][15][16][17], and successful results are obtained in these studies. In [12], the design and fabrication of a microstrip band-pass filter based on quadruplet geometry is reported, where the filter resembles elliptic function near passband and Chebyshev filter in the stopband. Multi-band bandstop filters are designed by using embedded I-stubs within a microstrip structure in [15] at 2.5/6.78 GHz, whereas in [16] High Temperature Superconductor (HTS) is used for the fabrication of the bandstop filter for L-band applications and it is reported that HTS has better performance than their gold-based counterparts.…”

Design and implementation of fractional‐order microwave differentiator

“…Mostly, work had been done on the FODs which can operate hardly up to a frequency of few hundred MHz. So, the benefits of fractional calculus discussed so far can be taken to GHz range by using various techniques for the design and implementation of microwave filters [27][28][29][30][31][32]. In [27], compact dual-band bandpass filters using microstrip lines were designed using the hybrid-coded GA. Sanada et al [28] used the GA method for designing transmission line filters with open-circuited stubs in shunt configuration and continuously varying transmission line matching circuits.…”

“…Based on equal-length non-uniform coupled lines, a tripleband bandpass microwave filter was proposed by evaluating the system function of the filter in the Z-domain using discrete-time techniques and chain scattering matrices of transmission line elements [29]. Inverse Legendre filter response was derived in [30] and the filter implementation is shown in microstrip low pass configuration. Kim and Lee [31] demonstrated a method based on the Z-transform to cascade transmission line sections for the synthesis of unequal-length multi-section transmission lines for multiband applications.…”