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1. Flicker noise comparison of direct conversion mixers using Schottky and HBT dioderings in SiGe:C BiCMOS technology

Author

Rasmus S. Michaelsen, Michele Squartecchia, Kjeld M. Tamborg, and Tom K. Johansen

Subjects
Engineering, diode connected HBT, Electronic mixer, flicker (1/f) noise, Loss measurement, Noise measurement, Schottky diodes, Noise (electronics), Mixers, Frequency measurement, Schottky diode, Flicker noise, Mixer, Monolithic microwave integrated circuit, Diode, business.industry, Components, Circuits, Devices and Systems, Cutoff frequency, General Topics for Engineers, MMIC, Optoelectronics, business, Fields, Waves and Electromagnetics, Heterojunction bipolar transistors
Abstract

In this paper, we present flicker noise measurements of two X-band direct conversion mixers implemented in a SiGe:C BiCMOS technology. Both mixers use a ring structure with either Schottky diodes or diode-connected HBTs for double balanced operation. The mixers are packaged in a metal casing on an Arlon 25N substrate to shield the sensitive noise measurement. Conversion loss measurements of both mixers is performed both for on-wafer and packaged versions. The experimental results shows that the Schottky diode mixer exhibits a 1/f noise corner frequency of 250 kHz, while the diode connected HBT circuit demonstrates a 1/f noise corner frequency around 10 kHz.

Published
2015

2. Analysis and design of complex impedance transforming marchand baluns

Author

Rasmus S. Michaelsen, Tom K. Johansen, and Kjeld M. Tamborg

Subjects
Engineering, Reactance, Impedance matching, Phase (waves), Capacitors, law.invention, Mathematical model, Balun, law, Microwave theory and techniques, Insertion loss, Electrical impedance, Monolithic microwave integrated circuit, Aerospace, Ports (Computers), Photonics and Electrooptics, business.industry, Electrical engineering, Impedance, Components, Circuits, Devices and Systems, Communication, Networking and Broadcast Technologies, Complex impedance transformation, Capacitor, Signal Processing and Analysis, Integrated circuit modeling, MMIC, business, Fields, Waves and Electromagnetics, Marchand balun
Abstract

A new type of Marchand balun is presented in this paper, which has the property of complex impedance transformation. To allow the Marchand balun to transform between arbitrary complex impedances, three reactances should be added to the circuit. A detailed analysis of the circuit gives the governing equations. To verify the theory, a design and electromagnetic simulation of a lumped element Marchand balun is made in a SiGe BiCMOS technology. The lumped element impementation is favorable because capacitors are placed where the additional reactances should be added. Thus it is possible to absorb a positive reactance by reducing a capacitor. At the design frequency of 10.5 GHz it matches 50Ω to 50 - j66Ω. It has an insertion loss of 5.1 dB, an input reflection of −20.8 dB, as well as phase and magnitude imbalance better than 0.2° and 0.12 dB, respectively.

Published
2014