In the last years, Wireless market has shown an incredible growth, exceeding expectations. This paper presents a fully integrated folded mixer in a BiCMOS 0.35 μm technology for the 5 GHz band, according to the IEEE 802.11a WIFI standard. To make possible a comparison, two designs are presented: a folded mixer, and a classical Gilbert cell. In both designs all passives devices are on chip, including integrated inductors which have been designed by electromagnetic simulations. This work demonstrates the improvement in gain and linearity of a folded mixer comparing to a classical Gilbert topology, at expense of a little increase in power consumption. This implies that, unlike the Gilbert mixer, in a low voltage application, the folded topology would present still good performance.
A fully-integrated SiGe wide band amplifier implemented in a standard low cost 0.35 &mgr;m process up to 12 dB of gain
and a bandwidth of 3-10 GHz is presented. This circuit is divided in 3 stages.
The first one is the input matching where the use of an inductively degenerated amplifier is expanded by embedding the
input network of the amplifying device in a multisection reactive network so that the overall input reactance is resonated
over a wider bandwidth. The second stage is a cascode transistor to obtain a great power gain and a high isolation
between input and output ports. In adition, by adjusting the area and the multiplicity of these transistors, we can reduce
the noise figure of the circuit. Finally at the output a new technique is used to increase the bandwidth. This technique is
based in the replacement of the load resistor by a shunt-peaking resistor composed by an inductor and a resistor. The
addition of an inductance gives an output impedance that remains roughly constant over a broader frequency range.
Chip dimensions are 0.665 × 0.665 mm2 and power dissipation is 39 mW, drawn from a 3.3V supply. The noise figure
ranges from 3.5 to 7.5 in the band between 2 GHz and 8.5 GHz. Finally, the circuit core draws 5.3 mA from a 3.3-V
supply. All this results were measured in a probe station.
European standard DVB-T (Digital Video Broadcasting - Terrestrial) has already proven its exceptional features,
including the possibility to receive broadcast services also with portable devices and even in receivers with a limited
mobility such as cars. This paper presents a fully integrated LC voltage controlled oscillator (VCO) in a low cost 0.35
μm SiGe technology for DVB-H standard. To obtain VCO specifications system simulations have been done. The
designed VCO is suitable to operate with ZERO and LOW IF receiver architectures. To integrate all the VCO
components, it oscillates at double of the frequency band, from 940 to 1724 MHz. In order to sweep the whole frequency
range, the tank is composed of an array of switched capacitors together with the varactors. The integrated inductors have
been designed by electromagnetic simulations using Momentum(C). Techniques like using a capacitor divider, biasing the
transistor for minimum noise and emitter degeneration have been utilized to improve phase noise requirements. The
obtained phase noise is -108 dBc/Hz at 100 kHz offset and the power consumption, including the output buffers, is 28
The performance of stacked and miniature three-dimensional spiral inductors is analyzed and compared to standard
planar coils. For this purpose, nine of these new structures have been fabricated in a 0.35-μm four-metal SiGe process.
According to the measurement results, some of the proposed stacked inductors occupy only 48% of the area of a
conventional planar inductor with the same inductance value and work frequency. The area reduction is even more
significant with the miniature 3-D structures, which occupy only 22% in some cases, and translate the inductor self-resonance
frequency to higher values than the conventional stacked inductors. In spite of this area reduction, these new
structures employ metal levels close to the substrate, which significantly degrades the quality factor. So the standard
planar coils continue to be the best choice if the designer requires high-quality inductors. However, stacked and 3-D
miniature structures could be a better solution if the area saving is the circuit major priority.
In this paper models for the capacitance of cross integrated varactors based in the PN junction are presented. Three different approximations are assumed, in order to reproduce the measured results of the capacitance. The relative error with the measured capacitance is under 10% in all cases.
This paper deals with the design and modeling of integrated spiral inductors for RF applications by means of a general purpose Electromagnetic (EM) simulator. These tools allow optimizing flexibly the inductor layout structure. The inductor performance can be obtained by using a three-dimensional design tool or a two-dimensional one. Planar 2-D or so called 2.5-Ds simulators are faster and accept complex coil geometries. We have used one of these simulators, the Advanced Design System planar EM simulator, Momentum, from Agilent.
The inductor quality factor (Q) is limited, among other phenomena, by the series resistance of the metal traces and the substrate losses. Therefore the simulator requires an accurate set up of the process and simulator parameters and a correct algorithm to model metal thickness to rely on simulation results. In this paper we analyze and compare these different approaches.
A high-quality factor inductor library on a 0.35 μm SiGe technology at 5 GHz is also designed in this work using the proper simulator set up. Nine of the inductors have been fabricated and measured to test the simulator reliability. Measurements taken over a frequency range from 500 MHz to 10GHz show a good agreement with 2.5-EM simulations.
In the last years, WIFI market has shown an incredible growth, exceeding expectations. This paper presents the design of two fully integrated LNAs using a low cost SiGe 0.35 um technology for the 5 GHz band, according to the IEEE 802.11a WIFI standard. One LNA has an asymmetric configuration and the other a balanced configuration. A comparison between the two LNAs has been made. All passives devices are on chip, including integrated inductors which have been designed by electromagnetic simulations. This work demonstrates the feasibility of a low cost silicon technology for the design of 5 GHz band circuits