Analytical Design of Wire-Bonded Multiconductor Transmission-Line-Based Ultra-Wideband Differential Bandpass Filters

Abstract

A systematic design process of ultra-wideband differential bandpass filters based on wire-bonded multiconductor transmission lines is presented. The topology is thoroughly analyzed by means of analytical design equations that provide some insights into the physical behavior of the proposed structure. Single-and double-section configurations are introduced and exact closed-form design equations are derived to design differential filters with either a Butterworth or Chebyhsev frequency response. To validate the design procedure, two differential filters are designed and fabricated with an equal-ripple fractional bandwidth (FBW) of 100% and 60% (3-dB FBW of 145% and 97%), respectively. The measured differential-mode responses show a good in-band flatness with insertion losses lower than 1 dB and with high common-mode rejection levels greater than 20 dB. Experimental results demonstrate a good agreement with theory and prove that the proposed design methodology is useful for accurate and fast ultra-wideband differential filter synthesis.

Synthesis of Dual-Band Bandpass Filters With Short-Circuited Multiconductor Transmission Lines and Shunt Open Stubs

“…Therefore, at this point it is important to highlight the advantages of using multiconductor transmission lines instead of only a pair of coupled lines. The achievable values of Z 0 a and c as a function of the line width W and spacing S for several number of conductors k are shown in [27]. These curves were calculated by using the Rogers 4350B substrate with a dielectric constant of 3.66 and thickness of 30 mils.…”

“…to get low MTL impedances (Z 0 a ) and high coupling factors (c) [27]. Prototype II does not allow narrow bandwidths, because of large stub widths would be needed.…”

“…In addition, it is remarkable that frequency ratio hardly varies with the MTL impedance. As this impedance must be low, the number of conductors has to be increased to achieve the desired MTL impedances [27], justifying again the use of multiconductor transmission lines instead of only a pair of coupled lines. Thus, prototype I is more appropriate when using higher frequency ratios and narrow bandwidths, whereas prototype II is better suited to wide bandwidths.…”

Diseño e Implementación de un Filtro Multibanda de 2 secciones para Comunicaciones Móviles con Líneas de Transmisión y Stubs en Abierto

“…Los recientes desarrollos de filtro multibanda (MPF) microstrip de banda ancha buscan un alto rendimiento, alta inmunidad al ruido, baja potencia de transmisión, tamaño reducido, bajo costo, y bandas anchas. (Sengupta, 2022), (Sánchez-Martínez, 2014) Se utiliza líneas microstrip para la implementación de estos filtros a altas frecuencias, ya que los elementos fijos LC (inductores y capacitores) tienen pérdidas y sus valores comerciales son muy limitados. Para la transformación de elementos electrónicos a su equivalente en líneas de transmisión se emplean dos conceptos.…”

Small Size Dual-Band Bandpass Filters with Multiconductor Transmission Lines and Shunt Open Stubs

“…Nevertheless, using more than two coupled lines can offer more variety in the kind of responses that can be achieved. For example, multiconductor transmission lines (MTL) have been used for synthesizing wide and ultra-wideband filters [8]- [10].…”