G. Felic

A 60-GHz transceiver on CMOS

Modern systems require transceivers that deliver gigabit speeds are smaller in size with lower power consumption and cost than existing technology consequently high speed transceivers operating at 60 GHz and delivering multi-gigabit per second are receiving significant research interest. This paper describes a 60-GHz transmitter developed and tested on a 130-nm CMOS process.

Investigation of Frequency-Dependent Effects in Inductive Coils for Implantable Electronics

In this paper, we investigated how frequency-related effects influence the resistance of inductive coils used in wireless links for implantable electronics. In particular, we studied proximity and skin effect by employing numerical simulation. In order to elicit these effects, simple three-turn coils with varying fill factors were studied. We found that proximity effect depends strongly on the fill-factor ratio. This is verified experimentally with a seven- and 17-turn coils of the same inner and outer diameter. We found that the coil with lower fill factor has better performance in terms of its quality factor at higher frequencies. A maximum Q increase of 29% was observed for the seven-turn coil compared to the 17-turn coil.

Issues in the Implementation of a 60GHz Transceiver on CMOS

The spectrum around 60 GHz is available for unlicensed operation in many regulatory domains including the USA, Japan, Canada and Australia. One of the applications of this spectrum is for short range communication systems. These systems are designed to deliver gigabit speeds, consuming small amount of power in small form factor. The small factor is achieved because passive components scale with carrier frequency and at 60GHz components such as: transmit receive filters, passives and antennas are candidates for inclusion on the die. Integrating RF, mixed signal and digital components is another important step towards reducing system cost and form factor. In order to achieve low cost and high digital integration CMOS is the process of choice. Unfortunately compared to other much more expensive processes such as SiGe and GaAs, CMOS has greater process variability, lower carrier mobility constants, and smaller device breakdown voltages all of which make millimeter wave RF design particularly challenging. In this paper we outline the issues in the implementation of a Gigabit per second 60GHz Transceiver-on-Chip using CMOS.

Implementation of a Gigabit Per Second Millimetre Wave Transceiver on CMOS

Modern systems require transceivers that deliver gigabit speeds, are smaller in size, and have lower power consumption and cost. This motivates research to develop transceiver-on-chip and transceiver-in-a-package technologies. Recent advances in millimetre wave electronics have meant that significant portions of the system can now be integrated onto a single substrate or package. In order to achieve low costs and high digital integration CMOS is the process of choice as CMOS is the standard and a cost effective process for building digital circuits. Unfortunately compared to other much more expensive processes such as SiGe and GaAs, CMOS has greater process variability, lower carrier mobility constants, and smaller device breakdown voltages. This makes millimetre wave wireless transceiver on a chip design particularly challenging. In this paper we outline the development of a gigabit transceiver-on-chip using CMOS and outline the performance of the fabricated components.

High-Q flexible spiral inductive coils

A limitation on the optimal design of inductive coils for wireless power transfer is its physical size. We investigated the effect of varying width and spacing of conductive trace of spiral inductive coils in order to improve its quality factor and hence power transfer efficiency between two coils. These spiral coils have inner and outer diameter of 23 mm and 36.5 mm, respectively. We found that for the same number of turns, quality factor Q increases with an increase in spacing. This is attributed to proximity effects in adjacent conductive tracks of the coil. An increase of Q at 6.78 MHz by 121% from the minimum value was achieved by systematically varying the different topologies. We conclude that an optimal topology of choice for a spiral coil is larger spacing and smaller number of turns.

An Integrated Transformer Balun for 60 GHz Silicon RF IC Design

A broadband monolithic transformer balun has been designed and fabricated at millimeter-wave frequencies. The balun is implemented on 0.13 um CMOS process and integrated with the 60 GHz mixer circuit. A measured amplitude and phase balance less than 3 dB and 5 degrees respectively over the 50-65 GHz frequency band was achieved. The designed device has advantages of small size, simple layout and wide operational frequency range.

Consumer radar: Technology and limitations

Recent advances in micro-electronics have created the possibility of building very low cost, very small, high performance single chip Radar systems. Concurrent with this technological advance, a diverse range of new applications for such radar systems is emerging. The coming consumer radar revolution is on the verge of entering the market place in areas including automotive radar, bicycle radar, micro-UAV radar, and many other applications. This short paper briefly describes the current state of the technology covering RF, signal processing and antenna systems. We also introduce recent work on performance limitations of such systems including radar information theory and its connections with quantum mechanics.

Study of heat sink EMI effects in SMPS circuits

EMC is an integral part of switching mode power supply (SMPS) design. An optimal SMPS could be considered as one which achieves the best possible compromise between power losses and EMI disturbances, both of which are directly related to the switching speed of the device. Thus the process of finding an acceptable switching speed becomes a critical part of the design process. This paper considers heat sink aspects of this power loss/EMI trade-off.

Closed-loop inductive link for wireless powering of a high density electrode array retinal prosthesis

A retinal prosthesis intended for rehabilitation of vision impaired patients will require continuous power supply in order to achieve real-time moving images. In this work, we explore the use of inductive coils fabricated using flexible circuit technologies for inductive powering of the implanted prosthetic device. We found that manufacturing technologies dictate the optimum operating frequency of the coil. For a minimum track width and spacing of 4 mils, the optimum frequency was found to be 2.9 MHz. We also looked at the distribution of electric and magnetic fields generated by the inductive coils in and surrounding the eye. These simulation results show that there are electric field concentrations around the conductive coils. Apart from the coils, we need to design an efficient circuit to drive the transmit coil and recover the transmitted power. In order to maintain optimal operation of the link, a closed-loop load modulation feedback operation is proposed. Adaptive control using back-telemetry of the induced voltage on the secondary side can close the power supply loop and result in optimum power transfer by boosting the supply voltage on the primary side when load is high and reducing this voltage when load is small.

Antenna gain measurements in the V-band: A single-antenna method

In this paper, a single-antenna gain measurement technique in the V-band is presented. The technique is simple and inexpensive as it uses standard antenna measurement equipment and it does not require antenna range calibration procedure. To the authors knowledge, this is the first millimeter wave antenna gain measurement presented that uses single-antenna method.