Design of a very compact U‐HI‐LO low‐pass filter using meander technique and quasi horn inductors for L‐band and C‐band applications

Abstract

ABSTRACTIn this article, a novel very compact low pass filters, using Hi‐Lo technique and meander method are proposed. The several proposed filters are designed using a modification along the microstrip line by addition of U form and a meander shape. The compact meander LPF consists of two thin microstrip lines, which are connected with 50‐Ω microstrip feed lines and thus with the both SMA connectors and a width microstrip patch placed in the middle of the structure. This meander Hi‐Lo topology has been placed on the RO4003 substrate with a relative dielectric constant εr = 3.38 and thicknesses h = 0.813 mm and a loss tangent of 0.0027. Additionally to a very good compactness, the structure exhibits simple design and fabrication, very low insertion loss in the passband of 1.5 dB, and it achieves a wide rejection bandwidth with overall 20 dB attenuation from 5.7 to 6.3 GHz. The compact low pass structure occupies an area of (0.337 λg × 0.253 λg) where λg = 60 mm is the wavelength at the cut‐off frequency 2.75 GHz. The simulated and measured results show good agreement and validate the proposed approach. Such compact filter structures are used in various microwave system applications. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2897–2901, 2016