Multilevel monolithic inductors in silicon technology

Multilevel monolithic inductors implemented in standard BiCMOS technology are presented. Use of top metal layers shunted with vias provides Q values approaching 10 at 2.4 GHz and above 6 at 900 MHz for a 2 nH inductor. There is no modification to the conventional wiring metallurgy and no need for extra processing steps     

Thinning of 2D and 3D Fractal Antenna Arrays with Bounded and Unbounded Fractal Distribution Functions for Celestial Communications

Fractal antenna arrays are geometry‐based thinned arrays having multiband applications. The major challenge of these arrays is their large number of elements at higher expansion factors. This article presents the thinning of fractal antenna arrays while maintaining an appropriate balance between the side lobe level and beam width by using various quantized fractal distribution functions. A 2D square fractal antenna array and 3DSierpinski gasket antenna array are considered in this article to validate the proposed distribution functions. Nearly one third of the antenna elements are thinned in each successive iteration except in the case of a one‐count distribution function. The proposed technique can simplify practical implementation and exhibits better performance for various parameters such as the side lobe level, side lobe angle, and half power beam width than fully populated fractal antenna arrays.     

Performance evaluation of the time delay digital tanlock loop architectures

This article presents the architectures, theoretical analyses and testing results of modified time delay digital tanlock loop (TDTLs) system. The modifications to the original TDTL architecture were introduced to overcome some of the limitations of the original TDTL and to enhance the overall performance of the particular systems. The limitations addressed in this article include the non-linearity of the phase detector, the restricted width of the locking range and the overall system acquisition speed. Each of the modified architectures was tested by subjecting the system to sudden positive and negative frequency steps and comparing its response with that of the original TDTL. In addition, the performance of all the architectures was evaluated under noise-free as well as noisy environments. The extensive simulation results using MATLAB/SIMULINK demonstrate that the new architectures overcome the limitations they addressed and the overall results confirmed significant improvements in performance compared to the conventional TDTL system.     

A 2.4-GHz silicon bipolar oscillator with integrated resonator

A 2.4 GHz fully-monolithic silicon-bipolar oscillator circuit implemented in a 12 GHz BiCMOS technology is presented. The integrated resonator circuit uses three different versions of a 2 nH multilevel inductor and a wideband capacitive transformer. The measured Q factor is 9.3 for the three-level inductor. An oscillator phase noise of -78 dBc/Hz is achieved at 20 kHz offset. The circuit dissipates 50 mW from a 3.6 V supply     

Two members of a widely expressed subfamily of hormone-stimulated adenylyl cyclases

cDNA encoding a hormone- and guanine nucleotide-stimulated adenylyl cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] (type 6) from rat liver and kidney has been cloned and expressed. This enzyme is stimulated by forskolin, guanosine 5'-[gamma-thio]triphosphate, and isoproterenol plus GTP but is not stimulated by beta gamma subunits of guanine nucleotide-binding proteins. A second form (type 5), which is 75% similar to type 6, has also been cloned. Both types 5 and 6 cDNAs have multiple messages. PCR-based detection of the mRNA for the type 5 and 6 enzymes indicates that both are widely distributed. Homology analyses indicate at least four distinct subfamilies of guanine nucleotide stimulatory protein-regulated adenylyl cyclases. Types 5 and 6 enzymes define one distinct subfamily of mammalian adenylyl cyclases. Diversity of one guanine nucleotide-binding protein-regulated effector may allow different modes of regulation of cell-surface signal transmission.     

Electromagnetic scattering from dielectric bodies

Far-field results obtained by two different methods are compared for the problem of electromagnetic scattering from dielectric objects. The two methods are the surface integral formulation, utilizing equivalent electric and magnetic surface currents, and the volume formulation, utilizing the equivalent electric polarization current. Triangular patches are used in the surface formulation and cubical cells are used in the volume formulation. The far-scattered fields obtained by the two methods are in good agreement, thereby validating both the approaches for the analysis of scattering problems. Numerical problems associated with the fields in the source region are also addressed