In Memoriam: Professor Roberto Sorrentino

The Society mourns the passing of Professor Roberto Sorrentino. The IEEE Life Fellow died in Italy on 3 March. Prof. Sorrentino ended his career at the University of Perugia, where he worked from 1990 to 2017. He founded a spin-off company, RF Microtech, in 2007. His research focused on numerical methods and CAD techniques for microwave and millimetre-wave circuits and antennas, including reconfigurable circuits and antennas based on RF MEMS. He published extensively, won numerous IEEE and MTT-S awards, chaired IEEE's Central and South Italy section, was Editor-in-Chief of IEEE Microwave and Guided Wave Letters from 1995 to 1998, and served on MTT-S's AdCom in 1998-2005 and 2011-2013.
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Large-Frequency-Ratio Waveguide Dual-Band Filter

A dual-band filter with a large frequency ratio is based on mode composite coplanar waveguide (MCCPW) approach. Both low and high bands of the dual-band filter can be designed independently with a high degree of design freedom. The filter can achieve a ten-fold frequency differential between the two bands, something usually hard to accomplish by conventional dual-band filter design techniques. All harmonics between the two bands can be suppressed via a cascaded low-pass filter and impedance matching structure to form a qualified dual-band frequency response. The MCCPW dual-band filter makes it a promising candidate for multiband systems, especially in 5G communication systems.
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Towards a Wideband Noise Parameter: The SKA-Low Example

A new proposal for a (long-sought) figure-of-merit for noise-extraction from well-spread source points is physically motivated and connects to matrix condition number and/or determinant. The key is selecting the correct noise temperature equation and removing any singularity due to the 1/(1-|Γₛ|²) factor. This approach was successfully applied to the low-frequency Square Kilometre Array (SKA-Low) 50-350 MHz band, despite an under-100-MHz tuner.
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Compact Harmonic Transponder for Insect Tracking

Passive harmonic transponders are used where the weight and size of active transmitters are impractical, e.g., for insect tracking. Designing even a simple transponder tag--a wire dipole antenna and a Schottky diode with a parallel inductance--for such applications is challenging. A new design combines the reliability of a printed circuit with the simplicity and small mass of a wire dipole antenna, with options for further miniaturization.
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Non-Galvanic Packaging for a Fully-Integrated Receiver

An MMIC packaging technique (demonstrated on a fully integrated D-band receive) employs a MMIC-to-waveguide transition using an on-chip probe mounted in the E-plane of a split-block waveguide. An artificial magnetic conductor suppresses cavity modes to improve coupling. The configuration showed low insertion loss (0.7 dB) while covering a very wide frequency range (105-175 GHz). Measurement showed average conversion gain of 23 dB at 110-145 GHz with a 10.6 dB average noise figure. The approach requires no galvanic contacts and imposes no limitations on MMIC dimensions.
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March Discounts for IEEE Remote Learning Network

This month’s discounted courses on the IEEE Learning Network again offer MTT-S members hundreds of continuing professional education courses created by in-demand industry experts; most courses offer Continuing Education Units (CEUs) or Professional Development Hours (PDHs). Until 4 April, purchase select courses (featured options include blockchain and smart grid, power electronic systems, cyber security, career networking, and much more, at a 30% discount. Use the code ILNMARCH and make sure you’re an active IEEE member.
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Miniaturized Bandpass Filter Uses TSV for THz

A miniaturized substrate integrated waveguide (SIW) bandpass filter applies Through-Silicon Via (TSV) technology to construct its THz cavity filter. The cavity filter exhibits a bandwidth of 0.051 THz centered at 0.331 THz, an insertion loss of 1.5 dB, and a reflection of higher than 15 dB in the passband.
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Waveguides for Uniform Kilowatt Microwave Heating

A kW-level, 2.45-GHz microwave applicator avoids reflections that cause hot and cold spots. The power-controlled microwave applicator uses three slotted (longitudinal or transverse) waveguides and power switching, so that each waveguide's input power is optimized. Overall, the approach improves heating uniformity up to 67%.
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Aligning High-Frequency Gyrotrons

A gyrotron's performance strongly depends on is proper alignment with the magnet, and alignment gets more challenging as frequencies rise. Research at China's National High Magnetic Field Center developed a triaxial flange that allowed users to align the gyrotron beam by centering its fluorescent signature on a sapphire window. 
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Frequency-Tunable Digital Power Amps

A digitally frequency-tunable switched-capacitor power amplifier (SCPA) operates from 1.4 to 2.5 GHz, controlling the center frequency via a commercially available programmable capacitor array. The prototype produced 21.7 dBm peak output power with 38.8% peak system efficiency while achieving 58.8% fractional bandwidth.
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