Diego Palombini

A novel hybrid active quasi-circulator for L-band applications

In this contribution a hybrid active quasi-circulator operating in L-Band is presented. E-pHEMT active devices mounted on ceramic substrate with copper metallization have been used. The proposed quasi-circulator is composed by active non-reciprocal phase shifters and classical passive combining structures to get the desired functionality. Insertion losses better than 2.1 dB, isolation higher than 20 dB in the 1.35 ÷ 1.65 GHz frequency band is obtained, while an isolation better than 30 dB over a 15% bandwidth. Port matching is better than 15 dB on couplers ports, while the splitter one reaches 10 dB. The overall quasi-circulator exhibits a 22 % operating bandwidth.

High-density mixed signal RF front-end electronics for T-R modules

In this contribution, several Multi-Functional Chips featuring different functionalities and integration levels are presented. A X-Band Core-Chip integrating a 6-bit attenuator, a 6-bit phase shifter, a T/R switch and a digital serial-to-parallel converter has been fabricated with 0.18 μm OMMIC ED02AH process. The MMIC exhibits 6 dB and 8 dB average insertion gain for transmit and receive mode respectively, full 360° phase coverage with 5.6° phase steps and 31.5 dB attenuation dynamic range with 0.5 dB amplitude resolution in less than 16 mm2. Two C-Band Multi-Functional Chips, one consisting of a bidirectional 6-bit phase shifter with on-board digital controls and the other integrating a 6-bit phase shifter, a buffer amplifier and a 5-bit attenuator have been fabricated with the 0.4 μm E/D GaAs process developed by SELEX Sistemi Integrati. The former exhibits full 360 degree phase coverage with 5.6° phase resolution in less than 18 mm2. The latter is an unidirectional MMIC featuring 8 dB average gain, full 360 degree phase coverage with 5.6° phase steps and 31 dB attenuation range with 1 dB amplitude resolution in less than 26 mm2.

Design and Experimental Performance of Diplexing MMIC Distributed Amplifier

An MMIC distributed amplifier with dual band frequency response and diplexing functionality is designed and measured. Using a band-pass artificial transmission line, two frequency bands, Spanish satellite broadcast TV band (11.7-12.5 GHz) and the mobile TV link (10.0-10.7 GHz), can be amplified and extracted at different physical ports. Experimental results exhibit quite good agreement with simulations and demonstrate the viability of these amplifiers in MMIC technology.

Novel broadband nonreciprocal 180° phase-shifter

In this contribution, a novel broadband 180° phase shifter, realized in 0.5 μm GaN HEMT technology developed by SELEX Sistemi Integrati, is presented. This new topology is based on the combination of two directive three-port elements with a four-port phase-shifting network: the proposed MMIC is featured by an average zero insertion loss, 180°±2° differential phase-shift and good port matching over the 3-7GHz operating bandwidth. The MMIC size is 3.5×3.4 mm².

Q-band down-converting module for Multi Pixel Camera receivers

Multi-Pixel Cameras represent an emerging architecture for arrays receivers, improving speed and accuracy of radio-astronomical sky surveys by means of a matrix of phased elements. This work faces the requirement of delivering to each pixel a high frequency LO signal (32GHz) without loss of synchronism: a new system architecture made up of an amplifying-multiplying chain and an amplifying-mixing section both integrated in the same 3×2mm2 chip is presented. The Q-band down-converting module, pumped by 4GHz local oscillator, operates in the whole 33–50GHz range with a really ultra-broadband IF section (1–18GHz).

An ultra-broadband 2–8 GHz GaN HEMT MMIC active combiner

In this contribution, a broadband active out-of-phase combiner designed in 0.5 μm GaN-HEMT technology developed by SELEX Sistemi Integrati is presented. The proposed MMIC is based on a distributed approach: exploiting the Drain line sharing, a dummy section and a single stage distributed amplifier, a 13.5 dB average differential gain, together with better than 10 dB input and output return losses and a CMRR better than 30 dB over the 2-8 GHz operating bandwidth are attained. The MMIC size is 2.9×3.3 mm2.

Downconverting Module Architectures for High Performance Multipixel Cameras

Multipixel cameras represent an emerging topology for arrays receivers, improving speed and accuracy of both security scanning systems and radioastronomical sky surveys by means of a matrix of phased elements. Difficulties in the generation and proper distribution to each pixel of the local oscillator signal still limit their use to frequency ranges below a few GHz or at least seriously affect the complexity of the implementable cameras. This work presents a full comparison between two possible system architectures, alternatively based on LO frequency multiplication or subharmonic mixing strategies, aiming to overcome the aforesaid limitations: design and performance of two compact test vehicles in MMIC technology, both operating in the Q-band frequency range with ultrabroadband IF section, are reported.

A 6–18 GHz integrated HPA-DPDT GaN MMIC

In this contribution an integrated HPA-DPDT for next generation AESA TRMs is presented. The proposed circuit relies on a concurrent design technique merging switches and HPA matching network. Realized MMIC features a 3×5mm2 outline operating in the 6-18 GHz band with a typical output power of 2W, an associated PAE of 13% and 3dB insertion loss in RX mode.

Band-pass distributed power amplifier in monolithic technology for the LTE band

The design and simulated performance of a bandpass MMIC distributed power amplifier to cover the LTE uplink are described. Small- and large-signal simulations have been carried out to evaluate the amplifiers behaviour. Results suggest that the designed amplifier might cover the LTE specifications. The simulated amplifier performance obtained through electromagnetic simulation is encouraging for a future physical implementation.

Design of Sub-Harmonic Mixer MMIC for EHF Satellite Links

This paper presents the design flow of a compact GaAs MMIC for Extremely High Frequency (EHF) satellite communications. The proposed circuit enables sub-harmonic mixing capability and integrates a LO buffering section, thus allowing for low frequency and low power reference signal interface. Circuit design is described in detail providing a comprehensive view of the followed theoretical approach, starting from mixer core definition until the complete synthesis of LO/RF/IF interfaces. In particular, the design flow of an innovative three-conductor Marchand balun is deeply analysed. Fabricated MMIC operates in the 43.5–50 GHz band and results in a compact layout (2.4×2.4mm2) featuring a port-to-port isolation better than 25 dB with a typical conversion loss of 12 dB.