José Miguel Rocha-Pérez

A novel divider using the Gilbert's cell with Floating Gate feedback

A very high frequency analog divider using Floating Gate transistors [1] is presented. The design is based on the Gilberts cell [2–3], which is formed by a four-quadrant multiplier, and operates in voltage mode where all the transistors are in the saturation region. Simulation results in 0.5um technology show that this cell is useful for high frequency applications.

A novel CMOS exponential transconductor operating in weak inversion

A novel CMOS exponential transconductor which employs only three NMOS transistors operating in weak inversion, is presented. The main advantage of the proposed circuit is its wide range of exponential behaviour, which reaches up to five decades of current range, and above 10 μA to an input voltage range of 800 mV. The physical realisation is achieved in two forms: in the first one, the circuit is implemented with discrete MOS transistor arrays by CD4007 series; in the second one, the circuit is fully integrated in a 0.5 μm CMOS standard process. Simulated and experimental results of the proposed exponential transconductor are also presented.

A 910MHz/2.4GHz easily tunable dual-band antenna for power harvesting and sensor networking applications

This work presents a 910MHz/2.4GHz dual-band dipole antenna for Power Harvesting and/or Sensor Network applications whose main advantage lies on its easily tunable bands. Tunability is achieved via the low and high frequency dipole separation Wgap. This separation is used to increase or decrease the S11 magnitude of the required bands. Such tunability can be used to harvest energy in environments where the electric field strength of one carrier band is dominant over the other one, or in the case when both carriers have similar electric field strength. If the environment is crowed by 820MHz-1.02GHz carries Wgap is adjusted to 1mm in order to harvest/sense only the selected band; if the environment is full of 2.24GHz - 2.52 GHz carriers Wgap is set to 7mm. When Wgap is selected to 4mm both bands can be harvested/sensed. The proposed antenna works for UHF-RFID, GSM-840MHz, 3G-UMTS, Wi-Fi and Bluetooth standards. Simulations are carried out in Advanced Design System (ADS) Momentum using commercial FR4 printed circuit board specification.

Fowler-Nordheim Tunneling Characterization on Poly1-Poly2 Capacitors for the Implementation of Analog Memories in CMOS 0.5 μm Technology

The experimental results of the Fowler-Nordheim characterization using poly1-poly2 capacitors on CMOS ON Semi 0.5 μm technology are presented. This characterization allows the development, design, and characterization of a new current-mode analog nonvolatile memory. Experimental results of the memory cell architecture are presented and demonstrate the usefulness of the proposed architecture.