Design of Low-Pass Filter Using Meander Inductor and U-Form Hi-Lo Topology With High Compactness Factor for L-Band Applications

Abstract

Abstract-In this paper, novel compact low-pass filters using Hi-Lo technique and meander method are proposed. Series of the proposed filters are designed by adding modifications along the microstrip line (meander inductor) and by using U-form topology. The size of the proposed filter can be reduced by 15% compared to the conventional filter while maintaining the optimal low-pass features. The compact meander LPF consists of two thin microstrip lines, which are connected with 50 Ω microstrip feed lines and a microstrip patch placed in the middle of the structure. The thin lines and the microstrip patch correspond to inductance and capacitance, respectively. The proposed meander Hi-Lo topology has been mounted on an RO4003 substrate with a relative dielectric constant ε r = 3.38, thickness h = 0.813 mm and loss tangent 0.0027. The compact L-band low-pass structure has a size of (0.263λ g × 0.175λ g ) where λ g = 57 mm is the wavelength at the cutoff frequency 2.85 GHz. In addition to a good compactness, the structure exhibits a simple design, very low insertion loss in the passband (L-band) of less than 0.3 dB, and it achieves a wide rejection bandwidth with a 20 dB attenuation from 5.3 to 6.3 GHz. The excellent LPF characteristics are verified through simulations and measurements where a good consistency can be observed. Such compact filter structures are expected to be used in various microwave system applications.

Design and Simulation of 2.4 GHz Microstrip Parallel Coupled Line Low Pass Filter for Wireless Communication System

“…By allocating an attenuation pole close to the cut-off frequency, a sharp roll-off skirt was achieved in [12]. However, only one attenuation pole was excited in the stopband [13] all three attenuation poles are far away from the desired low passband, so the roll-off skirt near the cut-off frequency has not been increased so much [14].…”

LPF/dual-BPF/UWB-BPF reconfiguration utilizing DGS resonators and lumped capacitors

“…With the rapid development of wireless communications, there is an urgent need for designing microwave filters with various behaviors. More studies have been conducted to achieve low-pass response of the filter as well as the bandpass behavior to satisfy the demands of recent wireless technologies with constrained specifications like small occupied area, high selectivity, enhanced roll-off rate, wide rejection band, and low passband insertion loss [1][2][3][4]. There are different techniques to achieve the desired filter behavior such as defected ground structures (DGSs) for achieving wide stopband behavior [5,6] and also it can be used to miniaturize the filter structure [7].…”

Compact tunable U-Hi-Lo low pass filter using quasi C-shaped stubs

“…One of the techniques used was cascaded technique where resonators are placed in horizontal or vertical topology, but it needs a larger occupied area in addition to larger coupling between resonators is occurred [3,4]. Other techniques can also be used to improve the behaviour of the low pass filter such as stepped-impendence resonators (SIR) [5,6], defected ground-plane structures (DGS) [7][8][9][10], combination of DGS and DMS [11], interdigital line resonator (ILR) [12], and meander-loop resonator [13], meander inductor [14,15], complementary split-ring resonator (CSRR) [16], and combination of SIR and DGS [17].…”