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A set of monolithic low-noise amplifiers have been designed and realised making use of an advanced industrial GaAs 70 nm metamorphic technology with high indium content. Operating frequencies of the realised amplifiers span from C-to W-band, with resulting performance in line with the requirements of many advanced radioastronomy applications. As an example, 2.7 dB NF from 75 to 90 GHz associated to...
Analysis and design of a compact wideband downconverter module for EW applications are presented in this paper. Architectural and circuit solutions trade-offs are described and related to the module's electrical and mechanical requirements and the key components characteristics. RF chain simulations and their comparison with measurements of the manufactured module are finally illustrated.
An alternative LNA design flow that addresses some of the typical issues connected with MMIC realisation is given in this contribution. The role of the input matching network is highlighted and investigated for low noise applications. Following the proposed design flow, an LNA test vehicle has been realised. The LNA's noise figure is less than 0.55 dB while its associated gain is better than 35 dB...
The multi-device Power Amplifier even and odd-mode stability is being tested using the Freitag approach. Results are verified by means of the time domain response of a sample circuit. Limitations are discussed and a possible extension of the method is proposed.
In this paper a new test bench for the measurement of FETs dynamic output I/V characteristics is presented. The characterization is carried out generating asymmetrical voltage signals at the gate of the device while the load at the drain terminal is varied. The experimental results obtained performing on-wafer measurements of a 1 mm GaAs PHEMT using the proposed test bench, successfully compare with...
In this contribution the possible applications, technology, design and measurements of a W-Band high gain LNA are given. The main features of the four stage LNA can be summarised as following: a 25 dB average gain with plusmn2 dB ripple from 70 to 105 GHz, where gain is higher than 21 dB on the entire 70-110 GHz range. LNA predicted noise figure is 2.7 dB between 80 and 95GHz and less than 3.2 dB...
Active terminations are helpful when dealing with planar antenna arrays. In fact, some antenna elements may be used as dummy ones to prevent electromagnetic field asymmetries. Such antennas should be terminated on loads that are as low noise as possible so as not to disturb the neighbouring active antennas. By using the proposed methodology, an active 50 Omega, low noise termination with an equivalent...
Gallium Nitride's superior physical properties, in comparison with other semiconductors, make GaNHEMT active devices a prime candidate in the implementation of next generation transmitters for radar systems, 3G/4G base stations and WiMAX. In this contribution, the characterization, modelling and verification of different families of high efficiency, high- power devices manufactured at SELEX Sistemi...
Controlled attenuators are key elements in a phased array's beam forming network and generally in all those systems requiring accurate control of the RF signal's amplitude and phase. Therefore the realisation of constant- phase digital attenuators is essential to obtain advanced system performance. A reactive element has been inserted in the traditional T topology digital attenuator to obtain equiphase...
Design issues of digitally controlled attenuators are considered: the parasitic phase shift effect, occurring with every change in the attenuator cell state, is highlighted, investigated and corrected. The technique adopted consists of inserting an appropriately sized capacitor in the attenuator cell topology, compensating for the above-mentioned parasitic phase shift. A design equation is inferred...
The role of the impedance load when dealing with noisy two port networks is investigated. Its value acts directly on input and output return losses (IRL and ORL) that can be simultaneously achieved once input load has been fixed to an arbitrary value. A novel design chart, obtained after examining constant mismatch circles, is introduced, where optimum trade-off between IRL and ORL is promptly identified...
The role of the impedance load when dealing with noisy two port networks is investigated. Its value acts directly on input and output return losses (IRL and ORL) that can be simultaneously achieved once input load has been fixed to an arbitrary value. A novel design chart, obtained after examining constant mismatch circles, is introduced, where optimum tradeoff between IRL and ORL is promptly identified...
In this contribution a set of MMICs' design and test is presented. The circuits have been designed for the synthesis of an RF beam forming network intended for focal plane array radioastronomy receivers
In this contribution a group of MMICs' design, measurement, test and reverse engineering considerations are presented. The circuits have been designed for the synthesis of a beam forming network intended for focal plane array radioastronomy receivers
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