A Coupled-Line Band-Stop Filter With Three-Section Transmission-Line Stubs and Wide Upper Pass-Band Performance

Abstract

Abstract-A novel band-stop filter with wide upper pass-band performance is proposed and discussed in this paper. This bandstop filter includes two three-section transmission-line stubs and a parallel coupled-line section. Because three-section transmission-line stubs and coupled-line section are used, this filter not only features good band-stop filtering property, but also has wide upper pass band. In order to verify this new filter circuit structure and its corresponding design theory, three groups of numerical examples are demonstrated. Finally, two practical band-stop filters using common microstrip technology are designed, simulated and measured. The simulated and measured results indicate that both the coupled-line section with weak coupling and two three-section stubs can improve the upper pass-band performance. Furthermore, the measured results of the second fabricated microstrip band-stop filter (Filter B) show that the 20-dB insertion-loss band-stop bandwidth at 0.46 GHz is 90 MHz and the 1.2-dB transmission coefficient upper pass band is from 0.66 GHz to 2.52 GHz. Thus, the highest pass-band frequency is extended to larger than five times of the operating center frequency of stop band.

Dispersion and Dielectric Effects on Reflection and Transmission of Electromagnetic Waves Propagating in Multiple Stages of Tape-Helix Blumlein Transmission Lines

“…β ni n is the same for the incident wave and the reflection wave in (5). As a result, the incident wave and reflection wave share the same dispersion relation in the ith stage helical Blumlein line.…”

“…Transmission line is a device which can be employed to transport and propagate electromagnetic waves in different frequency bands, and it has important applications in power system [1,2], electromagnetic communication technology [3], signal measurement [4,5], pulse delay and transmission [6][7][8][9][10][11][12][13], and pulsed power technology [14][15][16]. Usually, the transmission line has intrinsic power capacity and working band.…”

Design Filters Using Tunable E-Shaped Dual-Mode Resonators for Lower-Ultra-Wideband and Upper-Ultra-Wideband Applications

“…For obtaining a compact size, uniform half-wavelength resonator is bent and then the traditional E-shaped resonator is formed. Actually, this structure may also be considered as a stub-loaded resonator [22][23][24]. In previous reports, traditional E-shaped resonator structures are basically used for the design of narrow band (fractional bandwidth less than 10%) filters and seldom be used in the design of wideband filters [25][26][27].…”

Effects of the Inductive Port of Blumlein Transmission Line on the Reflection and Transmission Characteristics of Electromagnetic Waves

“…Transmission line (TL) is an important device for guiding and propagating electromagnetic waves in a special band, and it has been widely used in communications [1,2], pulse modulation and signal measurement [3][4][5][6], microwave technology [7][8][9][10] and pulsed power technology [11][12][13][14][15]. Every TL has its own characteristic impedance, and the impedance of a dispersive TL changes in line with the work frequency [15,16].…”