Compact highly selective passive notch filter for 3.1–5 GHz UWB receiver system

Abstract

This paper deals with the design of highly selective passive notch filter working at 2.4 GHz for 3.1-5 GHz UWB receiver system. The proposed filter aims to enable IEEE 802.11 b/g and UWB standard coexistence in the same terminal device. The filter topology is composed of two paths: the first path contains an all-pass function while the second path contains a band-pass one. By this way, the signal is divided at the circuit input and is combined at its output forming a notch response that exhibits a high rejection at the center frequency of the band-pass filter function. Experimental prototype implemented on Rogers4003 multilayer substrate is built in order to show the benefit of this concept design.

High-Performance Magnetoinductive Directional Filters

“…Larger values of µ were investigated and found to reduce losses and increase the passband of the bandpass channel and the notch depth. Stopband rejection can be greatly improved by fine-tuning 𝜆 according to Equation (21). For parameters in Table 1, the value of 𝜆 required for infinite rejection is 0.79, well within range for the coupling tuning mechanism.…”

“…Figure 4b shows the frequency dependence of scattering parameters for filters with lossy MI (1) and resistive narrowband (2) terminations for κ = 0.6, κ c = 0.3, Q = 200, and λ = 0.8746 from Equation (21). Both cases demonstrate excellent directional filtering with reflectance mostly <−30 dB within the passband, as well as infinite rejection at resonance.…”

“…However, there is an impact on filter performance; namely, port 3 is no longer fully isolated, the passband of port 2 reduces, and reflectance at port 1 is improved. Figure 4b shows the frequency dependence of scattering parameters for filters with lossy MI (1) and resistive narrowband (2) terminations for 𝜅 = 0.6, 𝜅 𝑐 = 0.3, 𝑄 = 200, and 𝜆 = 0.8746 from Equation (21). Both cases demonstrate excellent directional filtering with reflectance mostly <−30 dB within the passband, as well as infinite rejection at resonance.…”

“…Lumped element and waveguide formats have been developed for frequencies ranging from VHF to millimetre wave [8][9][10][11][12][13][14][15]. Two-port filters with high attenuation have also been developed and use multipath cancellation, reflection, or absorption to achieve infinite rejection [16][17][18][19][20][21][22][23]. Applications include transmit/receive modules, multiplexers in ultra-wide-band antennas, and superheterodyne receivers [24][25][26][27][28].…”

Tunable channelised bandstop passive filter using reconfigurable phase shifter

“…In [18], it was demonstrated that a highly selective bandstop filter response can be obtained at a fixed frequency f 0 when a bandpass branch designed at f 0 is combined to a PS branch that acts as a bypass signal inverter network. In an ideal case, the output signal is cancelled at this frequency when the signals propagating through the two branches are combined at the output with the same amplitudes but with 180° of phase difference.…”