Substrate integrated waveguide variable PIN-diode attenuators
Date
2018-10-24
Authors
Luciani, Gabriela
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Abstract
Due to the increase in broadband networks and the demand for data rate and operating frequency, such as mobile broadband, automotive radar, and communication systems, the development of new devices that can offer different applications and still provide good integration is highly necessary for communication systems. These devices need to have a low-cost profile, compact size, and high efficiency. Moreover, circuits which can control the signal strength are wanted in these communication systems. For manipulating large signals, attenuators are good candidates since they offer a lower power consumption. As the control element in variable attenuators, PIN diodes have been used due to their functionality as a variable resistance when used at high frequencies. There has been an effort in the development of substrate integrated waveguide (SIW) technology since it has demonstrated a good compromise between rectangular waveguide (RWG) and microstrip (MS) besides presenting a low cost, light component and easy fabrication profile. The transition of the SIW structure allows many applications when combined with MS- or coplanar waveguide (CPW)-based devices. Also, due to the block size of SIW, which sometimes can be too large for some practical circuits, a novel guided wave structure derived from SIW components, half-mode SIW (HMSIW), also need to be investigated. In order to explore some of the applications of SIW and HMSIW transitions and to demonstrate the integration of surface-mount (SMT) components, in this work, a proposed HMSIW variable attenuator to operate in the X-band (considering the frequency range between 6 GHz and 10 GHz), an HMSIW variable attenuator to operate in the K-band, (between 18 GHz and 28 GHz) and an SIW-CPW variable attenuator to operate in the K-band, (between 18 GHz and 28 GHz) are developed to explore some of the applications of SIW and HMSIW transitions and to demonstrate the integration of these technologies with SMT components. The integration with SMT components is accomplished, and the attenuation goal of each structure, of about 6 dB, is achieved by adjusting the level of the DC bias applied to the PIN-diodes. A verification of the design procedure is accomplished by the experimental characterization of the HMSIW variable attenuator in X-band. The simulation and measured results present a good agreement, and the initial goal of 6 dB attenuation is achieved and verified by the measurements.
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Keywords
PIN diode, Substrate integrated waveguide, Half-mode substrate integrated waveguide, Variable attenuator