A new single balanced diode mixer with DGS cell lowpass filter

Abstract

In this paper, a single balanced diode mixer using harmonic‐suppressed defected ground structure (DGS) low‐pass filter (LPF) with dumbbell shape is presented. The frequency bandwidth selected is C‐band, with 5.72–5.82 GHz for RF, 5.58–5.68 GHz for LO, and 140 MHz for IF signals. A rat‐race hybrid is designed for the accomplishment of the single balanced type of mixer. A low‐pass filter using DGS is used for good conversion loss and unwanted 2nd and 3rd harmonic suppression. The mixer is compared to a reference mixer with conventional low‐pass filter. When an LO signal with power of 4 dBm at 5.635 GHz is injected, a conversion loss of 6.2 dB is observed for the mixer. Also, LO‐to‐RF and LO‐to‐IF isolations of 30 dB and 40 dB are obtained, respectively. This mixer can be used in the area for wireless LAN application. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 423–425, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20489

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