The multiport circuit theory was initially developed in the 1970s by scientists for accurate automated measurements of the complex reflection coefficients in microwave network analysis. These multiport pioneers highlighted its usefulness in microwave low-cost circuit characterizations (S-parameters). Since 1994, the multiport techniques were further developed for microwave and millimeter wave radios. Several multiport architectures for specific applications such as communication transceivers, automotive radar, or imagery have been developed and implemented.

Basically, the multiport is a passive circuit composed of several couplers interconnected by transmission lines and phase shifters. Its specific architecture and design are strongly related to the target application and the operating frequency. The multiport acts as an interferometer; its output signals are linear combinations of phase shifted input signals. By using the appropriate circuit design and appropriate devices connected to the output ports, this circuit can provide specific functions such as reflection coefficient, distance or modal measurements, quadrature downconversion, or direct modulation of microwave/millimeter wave frequencies.

We invite authors to submit original research as well as review articles that will stimulate the continuing effort in developing multiport technology and its applications. We are particularly interested in articles describing new fields of applications and novel front-end designs using multiport circuits covering operating frequencies from hundreds of MHz up to hundreds of GHz. Potential topics include, but are not limited to:

• Recent developments in multiport architectures
• Advances in fabrication technologies, miniaturization, multiport characterization, and modeling
• Multiport technology for microwave network analysis and instrumentation
• Multiport technology in ultra-high speed communications
• Multiport technology and its applications in radar and imaging sensors
• Multiport technology toward THz frequencies: challenges in design, fabrication, and characterization

Before submission authors should carefully read over the journal’s Author Guidelines, which are located at http://www.hindawi.com/journals/jece/guidelines/. Prospective authors should submit an electronic copy of their complete manuscript through the journal Manuscript Tracking System at http://mts.hindawi.com/submit/journals/jece/circuits.systems/mutna/ according to the following timetable: