Improved Designs for Highly Integrated Lowpass–Bandpass Filters

This study presents three dual-band lowpass–bandpass filters. The first handles lowpass and bandpass bands through its fifth-order third-order Chebyshev filter responses, respectively. uses circuits to achieve flexibility in cutoff frequencies fractional bandwidths. second is a higher-order filter: it with ninth-order responses. In general, an extra 50- $\Omega $ transmission line might be required connect each port conveniently external circuit for the or proposed filter, which could increase area. third notation="LaTeX">$\lambda /4 impedance transformer near facilitate connections circuits. Each of filters has systematic design procedure when band responses are given separately. addition, can provide rapid prediction use ideal simulations instead full-wave simulations.