Abstract-In this paper, several Defected Microstrip Structure (DMS) are used to suppress the first and second spurious responses in microstrip hairpin filters. The DMSs are integrated in filter structure, and therefore this method keeps the filter size unchanged. The DMS interconnection disturbs the current distribution only across the strip, thereby giving a modified microstrip line with certain stop band. The undesired spurious harmonics are suppressed through multiple transmission zeros which are added at these frequencies by designed DMSs. Experimental results verify that 25 dB suppression for the first harmonic and 40 dB suppression for the second harmonic, respectively, without affecting the main passband response. There is a good agreement between the simulated and measured results.
A novel harmonic-suppressed microstrip stepped impedance lowpass filter (LPF) using Defected Microstrip Structure (DMS) is proposed. In order to cause the spurious passband suppression, appropriate geometries of DMS resonators have etched in the low impedance sections. Due to the attenuation poles of two kinds of resonators, it is found that harmonic responses are not only suppressed effectively, but a wide stopband can be also obtained. A demonstration filter with cutoff frequency at 2.5 GHz has been designed, fabricated and measured. The proposed filter also exhibits a very wide stopband of 145% (referred to a suppression degree of 20 dB).
Abstract:In this paper, it is demonstrated that the first and second spurious passbands suppression in microstrip hairpin filters can be achieved by simply patterning appropriate geometries of several Defected Microstrip Structure (DMS) in parallel coupled sections. By properly tuning DMS resonator dimensions, multiple transmission zeros can be generated in the vicinity of spurious harmonics and a wide stopband can be obtained. Experimental results verify that 25 dB and 40 dB suppression for the first and the second harmonics, respectively, without affecting the main passband response. Keywords: hairpin filter, Defected Microstrip Structure (DMS), harmonics blocking Classification: Microwave and millimeter wave devices, circuits, and systems Microwave Engineering, Wiley, New York, 2004. [2] M. C. Velazquez-Ahumada, J. Martel, and F. Medina, "Parallel coupled microstrip filters with ground-plane aperture for spurious band suppression and enhanced coupling," IEEE Trans.
This paper presents a novel Parallel-Coupled Microstrip Line (PCML) bandpass filter by etching of some slot resonators on the strip for suppressing the first spurious response. These slots perform a serious LC resonance property in certain frequency and suppress the spurious signals. Slot on the strip that is called Defected Microstrip Structure (DMS). The DMS interconnection disturbs the current distribution only across the strip, thereby giving a modified microstrip line with certain stop band and slow-wave characteristics. The measured results show a satisfactory rejection level more than 30 dB at first spurious passband without affecting the passband response. Keywords: Parallel Coupled-Line Filter (PCML), Defected Microstrip Structure (DMS), spurious response suppression Classification: Microwave and millimeter wave devices, circuits, and systems
References
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.