Design Of Microstrip Lowpass Filter Research Articles

Design of Modified Jacobi Microstrip Lowpass Filter for L-Band Application

In this brief, a design of microstrip lowpass filter with the 1 GHz cutoff frequency is revisited, where a class of modified Jacobi polynomials is used for the filter design. The optimization procedure for these filters includes the passband return loss minimization and the roll-off factor enhancement using the magnitude correction of the transmission coefficient. Mentioned correction is performed by introducing the multiple transmission zeros such that LC ladder prototype filter can be realized symmetrically. Three seventh degree filters for L-band applications are realized and simulated: allpole, with a single and double transmission zeros. It is shown that, among these three stepped impedance lowpass filters realizations, the filter with simple transmission zeros offers the best performance.

Design of High Performance Microstrip LPF with Analytical Transfer Function

AbstractBy exploiting butterfly and T-shaped resonators, a new design of microstrip lowpass filter (LPF) is proposed and analyzed. The LPF is investigated in four sections. Analyzing initial resonator and its equation in detail, providing a sharp skirt by using series configuration, suppressing in middle frequencies and suppressing in high frequencies are focused in each section, respectively. To present a theoretical design, LC equivalent circuit and transfer function are precisely calculated. The measured insertion loss of the LPF is less that 0.4 dB in frequency range from DC up to 1.25 GHz, and the return loss is better than 16 dB. A narrow transition band of 217 MHz and a roll-off rate of 170.5 dB /GHz are indicative of a sharp skirt. By utilizing T-shaped and modified T-shaped resonators in the third and fourth sections, respectively, a relative stopband bandwidth (RSB) of 166 % is obtained. Furthermore, the proposed LPF occupies a small circuit of

Design of Microstrip Lowpass Filter with Sharp Roll-off using Elliptical and Radial Resonators

AbstractA new microstrip lowpass filter with sharp roll-off and high suppression level in stop-band is presented. To achieve the lowpass filter with high performance, coupled T-shaped, elliptical and radial resonators are adopted. New formulas for calculating

Design of Microstrip Lowpass Filter Using bend Configuration with Excellent sharpness in Transition Band

Abstract In this letter, a microstrip lowpass filter (LPF) using bend configuration with several excellent features such as a compact size, great roll-off rate and high rejection in the stopband is presented. This structure is composed of a spiral transmission line loaded by several stepped impedance and T-shaped resonators. The cut-off frequency of the proposed filter is equal to 2.73 GHz and the transition band is from 2.73 up to 2.82 GHz with –3 and –20 dB attenuation point, respectively, which represents a very high sharpness in the transition band. To achieve a –40 dB rejection level in the stopband, multiple open stub and T-shaped patches are utilized. An acceptable agreement between EM-simulation and measurement results is observed.

Design of microstrip lowpass filter with wide stopband and sharp roll‐off using hexangular shaped resonator

A compact lowpass filter using a hexangular shaped resonator is presented. The designed lowpass filter has a −3 dB cutoff frequency of 2.97 GHz. The stopband bandwidth for the attenuation level of −20 dB is from 3.32 GHz up to 21 GHz, and the circuit only occupies 10.04 × 10.92 mm2. The structure is simulated, fabricated and measured. Both simulation and measured results are presented and compared and there is good agreement between them. The insertion loss in the passband is <0.06 dB and the fabricated filter presents a sharp transition band from 2.97 to 3.32 GHz for the attenuation level of −3 and −20 dB, respectively.

Design of microstrip lowpass filter with compact size and ultra-wide stopband

A new microstrip lowpass filter with compact size and ultra-wide stopband is presented. To achieve a compact design and ultra-wide band rejection, both triangular patch resonators and polygonal patch resonators are introduced in the filter. To reduce the circuit size of the filter further, the meander transmission line is also adopted in the design. A demonstration filter with 3 dB cutoff frequency at 0.85 GHz has been designed, fabricated and measured. Results indicate that the proposed filter is able to suppress the 14th-harmonic response referred to a suppression degree of 15 dB, together with a small size of 0.089 λg × 0.081 λg, where λg is the guided wavelength at 0.85 GHz.

Design of microstrip lowpass filters with wide stopband and high attenuation

In this reported work, novel microstrip lowpass filters featuring wide stopband and high attenuation have been developed. These filters are composed of multiple open stubs and short-end coupled lines. By properly selecting the electrical lengths of the open stubs and short-end coupled lines, transmission zeros can be generated in the vicinity of harmonics and a wide stopband can be obtained. Detailed design procedures are provided; moreover, agreement between measured and theoretically predicted results demonstrates the feasibility of the proposed filter.