International Journal of Electrical and Computer Engineering (IJECE) Vol. 4, No. 6, December 2014, pp. 902~908 ISSN: 2088-8708  902 Journal homepage: http://iaesjournal.com/online/index.php/IJECE A Compact SIW Mixer for Millimeter-Wave Applications Abdelkhalek Nasri * , Hassen Zairi * , Ali Gharsallah * * Unit of Research in High Frequency Electronic Circuits and Systems, Faculty of Sciences of Tunis, Tunis, Tunisia Article Info ABSTRACT Article history: Received Jun 12, 2014 Revised Aug 20, 2014 Accepted Aug 26, 2014 The present paper highlights an innovative broadband millimeter-wave single balanced diode mixer which is designed using a newly designed 90 substrate integrated waveguide (SIW) coupler and two cavities (SIW) filter. The mixer covers RF/LO operating frequency range which fluctuates between 10 to 12 GHz and IF port covers 2GHz. The proposed mixer exhibits a fairly low conversion loss of less than 10 dB and high port to-port isolations over the frequency band of interest as the simulated results make clear. Furthermore, the two cavities SIW filter is embedded to achieve a better image frequency suppression of about 28dB. Keyword: Substrate integrated waveguide Single-balanced mixer Conversion loss Image frequency Copyright © 2014 Institute of Advanced Engineering and Science. All rights reserved. Corresponding Author: Abdelkhalek Nasri, Unit of Research in High Frequency Electronic Circuits and Systems, Faculty of Sciences of Tunis 2092 Tunis, Tunisia. Phone: +21671872600. Fax: +21671871666 Email: abdelkhaleknasri@yahoo.fr 1. INTRODUCTION A high performance mixer module is required in the design of modern microwave telecommunication system. In normal single balanced mixer [1] the microstrip branch line hybrid is usually used as coupler section. However the fabrication will be more complex due to the dimension of such hybrid which could be very small [2]-[13]. So as an alternative, there is an extensive investigation for the design of low-cost, high performance microwave and millimeter wave (MMW) passive components, including directional couplers using the Substrate integrated waveguide (SIW). For instance, in [14] we used SIW single-aperture coupler to design a high performance mixer. We achieve a better conversion loss at price of larger size of a SIW coupler than other devices in the mixer circuit [15] [16]. In this paper, we propose the concept of substrate integrated circuits (SICs) [17] in order to offer an attractive solution for low cost, compact, efficient and hybrid integration of different kinds of conventional planar and non-planar structures within the same substrate at microwave and millimeter wave frequencies. In addition to low conversion loss, this type of mixer can provide other attractive characteristics including good image frequency rejection. In this present paper, we will first of all describe the SIW filter, then discuss the design of the mixer, and finally present the results along with its electrical performances. 2. SIW FILTER DESIGN This section focuses on the principle of the substrate integrated waveguide technology and at the same time the design of the SIW filter. brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by Institute of Advanced Engineering and Science