Coplanar waveguide wideband bandpass filter and its application to ultra-wideband pulse generation

Abstract

A technique to design wideband coplanar waveguide bandpass filters is reported. The filter is realized by etching a slot on the ground plane around a gap on its central conductor and modifying the gap in the form of parallel lines. It is shown that the 3-dB fractional bandwidth of the filter can be varied from 60 to 110% by tuning the size of the slot aperture and the length of the parallel lines. Equivalent circuit and design steps are presented. Implementation area of the filter having passband 3.2-10.5 GHz is 0.90 k g  0.26 k g , k g being the guided wavelength at 6.85 GHz while 20-dB stopband is at least up to 18 GHz. Insertion loss is less than 2 dB up to 9 GHz. Area of the filter having fractional bandwidth 60% at 3.85 GHz is 0.67 k g  0.11 k g . Passband loss is within 1.5 and 20 dB stopband is at least up to 12 GHz. The proposed filter structure is very simple to integrate, and the ultra-wideband filter is used to generate an ultra-wideband pulse as defined by the US Federal Communication Commission. V C 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE 00:000-000, 2012.

A compact UWB bandpass filter with a notched band using a multistubs loaded resonator

“…Since the UWB bandpass filter based on a multimode resonator (MMR) was introduced in Ref. [ ], various types of MMRs have been proposed and applied in the design of UWB bandpass filters …”

“…[2], various types of MMRs have been proposed and applied in the design of UWB bandpass filters. [3][4][5][6] Obviously, UWB frequency band might be interfered with some narrowband RF signals existing in the same environment, such as wireless local-area network (WLAN), Worldwide Interoperability for Microwave Access (WiMAX), and so on. Then, UWB bandpass filters with notched bands to suppress these possible interferences are popular recently.…”