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The resistive switching behaviour observed in microscale memristors based on laser ablated ZnO and VO 2 is reported. A comparison between the two materials is reported against an active device size. The results show that devices up to 300 × 300 μm 2 exhibit a memristive behaviour regardless of the device size, and 100 × 100 μm 2 ZnO-based memristors have the best resistance off/on ratio.

Soft errors that affect flip-flops are a major issue in advanced electronic circuits. As technology scales, multiple bit errors become more likely. This limits the applicability of traditional protection techniques like triplication with voting or single error correction codes that can correct only one error. Multiple errors tend to affect adjacent bits, and therefore it is interesting to use error correction codes that can correct adjacent errors. The issue with these codes is that they require a large area and delay that limits their use to protect flip-flops in circuits. Presented are codes that can be implemented with low area and delay and can correct multiple adjacent errors.

A technique to design high-power and high-efficiency oscillators is proposed. The technique is based on the adoption of high-efficiency harmonic tuning strategies. A test vehicle has been designed and realised to operate at about 5 GHz. The resulting measured efficiency is higher than 51% with an output power higher than 27 dBm.

A new topology for a distributed power amplifier (DPA) is presented to maximise DC-RF conversion (i.e. for high output power). The topology is featured by vectorially combined current sources when loading power transistors into distributed output and input networks using impedance termination values gathered by device load pull. To the authors' knowledge, the output power achieved in this work is the best for DPAs within the frequency range up to 2 GHz.

The design, fabrication and test of X-band high-power monolithic SPDT switches in microstrip GaN technology are presented. Such switches have demonstrated state-of-the-art performance: they exhibit 1 dB on-state insertion loss and better than 37 dB isolation. Power- handling measurements have shown that no compression phenomenon occurs with an input power equal to 39.5 dBm at 10 GHz.

A new and simple approach for the measurement of active device dynamic output I/V characteristics is presented. Device characterisation is performed making use of multi-harmonic exciting signal and variable loads at the output port. The measurement bench has been used to characterise a GaAs 1 mm gate periphery PHEMT as a test vehicle. The results, obtained making use of the proposed setup, successfully compare with those obtained via traditional pulsed measurement systems.

The experimental results of an ultra-wideband high-efficiency power amplifier (PA) in GaN technology are presented. The active device is a HEMT with 1 mm of gate periphery. The realised PA operates from 0.8 to 4 GHz, showing a drain efficiency greater than 40% with an output power higher than 32 dBm in the overall bandwidth.

The design procedure and measurements of a C-band high-performance GaAs cryo-cooled low noise amplifier (LNA) are presented. The latter provides 30 dB gain, a noise figure (NF) lower than 0.12 dB (i.e. 8 K equivalent noise temperature) at 25 K operating temperature, with 35 mW DC bias power only. An appropriate scaling of the device gate periphery has been adopted to trade-off the LNA's NF and DC power consumption.

The experimental characterisation of a 38 GHz micromachined GaAs receiver is presented. The structure monolithically integrates a double-folded slot antenna and a Schottky diode on the same GaAs thin membrane. The measurements demonstrate that this approach has the potential for innovative circuit architecture development.

The correct definition of helix pitch profile in multisection helix travelling-wave tubes is fundamental to obtain the required performance. The impact of tolerances on helix pitch manufacturing is a relevant reason for significant degradation of the small-signal gain. A detailed study analysing the effectiveness of compensating the effect of helix pitch error by a cathode voltage adjustment is proposed.

A straightforward and efficient implementation of a custom concurrent watchdog processor for real-time control systems is presented. Emphasis is given to the techniques used for on-line checking the main processor activity without adding overhead, and to the advantages of a field programmable gate array implementation.

The problem of the shielded coplanar waveguide short-end discontinuity characterisation was formulated using the transverse resonance method. The resonant frequencies of the structure are computed by the full-wave electromagnetic field analysis. The validity of this approach was confirmed by satisfactory agreement between numerical and experimental results