No abstract

Abstract-A programmable high-frequency operational transconductance amplifier (OTA) is proposed and analyzed. A general configurable analog block (CAB) is presented, which consists of the proposed programmable OTA, programmable capacitor and MOSFET switches. Using the CABs, the universal tunable and field programmable analog array (FPAA) can be constructed, which can realize many signal-processing functions, including filters. A tuning circuit is also discussed. The proposed OTA has been simulated and fabricated in CMOS technology. The results show that the OTA has the transconductance tunable/programmable in a wide range of 700 times and the 3-dB bandwidth larger than 20 MHz. A universal 5 8 CAB array has been fabricated. The chip has also been configured to realize OTA-C 60-kHz and 500-kHz bandpass filters based on ladder simulation and biquad cascade.Index Terms-CMOS analog integrated circuits, continuous time filters, field programmable analog circuits, programmable circuits, programmable filters.

Antennas on-chip are a particular type of radiating elements valued for their small footprint. They are most commonly integrated in circuit boards to electromagnetically interface free space, which is necessary for wireless communications. Antennas on-chip radiate and receive electromagnetic (EM) energy as any conventional antennas, but what distinguishes them is their miniaturized size. This means they can be integrated inside electronic devices. Although on-chip antennas have a limited range, they are suitable for cell phones, tablet computers, headsets, global positioning system (GPS) devices, and WiFi and WLAN routers. Typically, on-chip antennas are handicapped by narrow bandwidth (less than 10%) and low radiation efficiency. This survey provides an overview of recent techniques and technologies investigated in the literature, to implement high performance on-chip antennas for millimeterwaves (mmWave) and terahertz (THz) integrated-circuit (IC) applications. The technologies discussed here include metamaterial (MTM), metasurface (MTS), and substrate integrated waveguides (SIW). The antenna designs described here are implemented on various substrate layers such as Silicon, Graphene, Polyimide, and GaAs to facilitate integration on ICs. Some of the antennas described here employ innovative excitation mechanisms, for example comprising opencircuited microstrip-line that is electromagnetically coupled to radiating elements through narrow dielectric slots. This excitation mechanism is shown to suppress surface wave propagation and reduce substrate loss. Other techniques described like SIW are shown to significantly attenuate surface waves and minimise loss. Radiation elements based on the MTM and MTS inspired technologies are shown to extend the effective aperture of the antenna without compromising the antenna's form factor. Moreover, the on-chip antennas designed using the above technologies exhibit significantly improved impedance match, bandwidth, gain and radiation efficiency

A linear, fully balanced, voltage-tunable CMOS operational transconductance amplifier (OTA) with large dc gain and wide bandwidth is described. The approach uses a twodifferential-pair transconductor with a cross-coupled input stage together with a negative resistance load for compensating the parasitic output resistance of the OTA. Since no additional internal nodes are generated, dc gain enhancement is obtained without bandwidth limitation. SPICE simulations show that total harmonic distortion at 1.42 V p -p is less than 1% with dynamic range equal to 66 dB at a power consumption of 2.7 mW from a single 5-V supply. As an example, the OTA is used to design a third-order elliptic lowpass filter in the very-high-frequency range, simulated in a standard 2 m CMOS process (MOSIS).The cutoff frequency of the filter is tunable in the range of 12-50 MHz.

A general topology for transconductance‐capacitor (Gm‐C) filters is presented that permits any continuous‐time analog Gm‐C filter to be analysed via a matrix‐description. Based on these matrices, explicit formulas are derived for the transfer function and the sensitivities valid for any Gm‐C filter topology. The approach leads to a useful relationship between the passive capacitor network of the filter and the degree of its transfer function. The matrix‐based approach is formulated especially for efficient use in computer‐aided analysis and design of Gm‐C filters, but ‘hand designs’ of Gm‐C IFLF and LF filters are given as illustrative examples. A new, more general definition of Gm‐C state‐space filters is proposed. Connections between the state matrices for voltage‐ and current‐mode state‐space Gm‐C filters are formulated and two canonical transformations are defined that convert state‐space filters into direct state‐space ones, i.e. those having only grounded capacitors. Copyright © 2003 John Wiley & Sons, Ltd.