Renato G. Bosisio

A new direct millimeter wave six-port receiver

A new direct conversion wide band (23 GHz-31 GHz) six-port millimeter wave receiver suitable for integrated circuit fabrication is proposed to satisfy mass-market wireless communications. The receiver contains one multi chip module (MCM) consisting of a wide band six-port junction, four RF detectors (Schottky diodes), video amplifiers and I&Q decoder. The prototype circuits are fabricated in hybrid integrated circuits, and the receiver topology is suitable for fabrication in microwave monolithic integrated circuits (MMICs). This new hardware receiver is proposed as a robust, rugged, low cost receiver for use in wide band wireless mass market QPSK communications. Hand held and laptop terminals for future e-mail/multimedia services are a prime example of communication equipment needing such receivers. BER measurements and simulation results are presented in the presence of noise, adjacent signal interference, local oscillator (LO) phase shift and LO phase noise.

A new direct millimeter-wave six-port receiver

A new direct conversion wide band (23 GHz-31 GHz) six-port millimeter wave receiver suitable for integrated circuit fabrication is proposed to satisfy mass-market wireless communications. The receiver contains one multi chip module (MCM) consisting of a wide band six-port junction, four RF detectors (Schottky diodes), video amplifiers and I&Q decoder. The prototype circuits are fabricated in hybrid integrated circuits, and the receiver topology is suitable for fabrication in microwave monolithic integrated circuits (MMICs). This new hardware receiver is proposed as a robust, rugged, low cost receiver for use in wide band wireless mass market QPSK communications. Hand held and laptop terminals for future e-mail/multimedia services are a prime example of communication equipment needing such receivers. BER measurements and simulation results are presented in the presence of noise, adjacent signal interference, local oscillator (LO) phase shift and LO phase noise.

A new six-port junction based on substrate integrated waveguide technology

A six-port junction based on the substrate integrated waveguide (SIW) technology is proposed and presented. In this design of such a junction, the SIW is first converted to an equivalent rectangular waveguide, then regular rectangular waveguide design techniques are used. In this structure, an SIW power divider and SIW hybrid 3-dB coupler are designed as fundamental building blocks. A six-port junction circuit operating at 24 GHz is fabricated and measured. Good agreement between simulated and measured results is found for the proposed six-port junction.

W-band multiport substrate-integrated waveguide circuits

Millimeter-wave passive circuits that are designed and fabricated in the form of substrate-integrated waveguide (SIW) are presented in this paper. A W-band SIW 90/spl deg/ hybrid coupler and multiport SIW circuit are made and synthesized on alumina substrate using metallized slot arrays. In order to connect the SIW circuits with WR-10 standard rectangular waveguides for measurement purposes, a new transition is also proposed and developed. Such millimeter-wave integrated passive circuits are developed for applications in radar sensors operating at 94 GHz. Performances of these circuits are evaluated and discussed on the basis of a series of S-parameter simulations and measurements. Excellent agreement between simulated and measured results is observed.

Ka-band analog front-end for software-defined direct conversion receiver

A six-port Ka-band front-end architecture based on direct conversion for a software-defined radio application is proposed in this paper. The direct conversion is accomplished using six-port technology. In order to demodulate various phase-shift-keying/quadrature-amplitude-modulation (PSK/QAM) modulated signals at a high bit rate, a new analog baseband circuit was specially designed according to the I/Q equations presented in the theoretical part. An experimental prototype has been fabricated and measured. Simulation and measurement results for binary PSK, quaternary PSK (QPSK), 8 PSK, 16 PSK, and 16 QAM modulated signals at a bit rate up to 40 Mb/s are presented to validate the proposed approach. A software-defined radio can be designed using the new front-end and only two analog-to-digital converters (ADCs) because the I/Q output signals are generated by analog means. Previous six-port receivers make use of four ADCs to read the six-port dc levels and require digital computations to generate the I/Q output signals. With the proposed approach, the load of the signal processor will therefore be reduced and the modulation speed can be significantly increased using the same digital signal processor.

A new 94-GHz six-port collision-avoidance radar sensor

A new 94-GHz collision avoidance radar sensor is proposed. The receiver front-end module is based on a six-port phase/frequency discriminator (SPD). The SPD, composed of four 90/spl deg/ hybrid couplers, is manufactured in a metal block of brass using a computer numerically controlled milling machine. Simulation and measurement S-parameters of the SPD are presented in the frequency band. New SPD computer models are generated and used in the system simulations. Preliminary measurements and system simulations performed to obtain the relative velocity of the target and its distance are presented. Statistical evaluations show an acceptable measurement error of this radar sensor.

Ka-band direct digital receiver

A new direct-conversion wideband (26-28.5 GHz) six-port receiver is proposed for mass-market wireless communications. This six-port receiver is designed to operate without the need for precise power reading and the use of a digital signal processor that is usually required in other receivers. The proposed receiver architecture is chosen to satisfy requirements of hardware receivers used in high-speed QPSK communications. The receiver contains a receiver front-end, QPSK demodulator, and carrier recovery module. A reverse modulation loop was used to provide a rapid carrier recovery. The maximum bit rate is determined solely by the limiting speed of the baseband module. This new hardware receiver is proposed as a robust, rugged, low-cost receiver for use in wide Ka-band wireless mass-market QPSK communications such as local multipoint distribution system services, which is a prime example of communication equipment requiring such receivers. Bit-error-rate results are presented versus the noise and reference signal phase shift.

An experimental study of the effects of harmonic loading on microwave MESFET oscillators and amplifiers

This paper reports an extensive experimental investigation of the effects of second harmonic loading on the performance of microwave GaAs MESFET oscillators and strongly driven amplifiers. The measurement system used is an active load system based on six-port techniques. Harmonic load pull measurements were obtained for the NE72084 MESFET; the measurements show how the second harmonic load can influence the power gain and the power added efficiency in strongly driven amplifiers. The device line characterization technique was combined with the harmonic load pull technique; the measurement results illustrate how the output power and the DC to RF conversion efficiency of an oscillator depend on the choice of the second harmonic load. Amplifier and oscillator circuits have been designed using these measurements; the circuits have been constructed and measured. The results validate the experimental approach used and clearly illustrate the importance of properly selecting the second harmonic load in amplifier and oscillator circuits. Significant improvements in gain, output power and efficiency have been achieved by properly selecting the second harmonic load.

A six-port direct digital millimeter wave receiver

A novel approach is proposed for direct demodulation of various digitally modulated signals at microwave/millimeter wave frequencies using a six-port phase/frequency discriminator (SPFD). The proposed six-port direct digital receiver is capable of handling PSK and QAM as well as their varieties. Preliminary measurements on demodulation of DBPSK signals at 26.5 GHz, 33 GHz and 40 GHz have revealed great potential of this new receiver.<<ETX>>

A new multiharmonic loading method for large-signal microwave and millimeter-wave transistor characterization

A multiharmonic loading method for nonlinear microwave and millimeter-wave transistor characterization using six-port techniques is presented. The system allows independent load tuning of an excitation signal and its harmonics. Load-pull measurements on a MESFET which have been performed at the fundamental frequency f/sub 0/ and at the second (2f/sub 0/) and third (3f/sub 0/) harmonics are discussed. The results highlight the importance of such measurement in designing and modeling nonlinear devices and circuits. The experimental results are found to be directly applicable for optimizing efficiency and output power in high-power MESFET amplifiers and MESFET frequency multipliers. >