Engineering Commons^™

Reflectivity Characterization And Identification Of Primary Reflection Path In Anechoic Chamber Analysis, Aloysius Aragon Lubiano, Christopher R. Brito, Newlyn Hui, Dean Y. Arakaki

Electrical Engineering

This paper presents an analysis of the reflectivity performance of the anechoic chamber. Measurements indicating the performance of the chamber-installed foam absorbers (described in a companion paper) are used to complete this analysis. This is followed by a comparison of the analysis results to chamber measurements taken in accordance with the free-space VSWR procedure [1]. Agreement between the analysis results and worst-case VSWR test measurements is within 1dB for a majority of reflection angles. In addition to chamber performance predictions, this paper describes a method of identifying primary reflection paths through interferometer calculations that compare all single bounce reflection path …

A Laboratory Course On Antenna Measurement, Samuel Parker, Dean Y. Arakaki

Electrical Engineering

This paper presents background information and experiment procedures for an antenna measurement laboratory course to be held in a new anechoic chamber at California Polytechnic State University. The lab consists of five experiments and one design project intended to give students practical experience with antenna measurement techniques and to creatively apply analytical skills to design, construct, and test antennas that meet given specifications. The experiments reinforce antenna principles including E-field polarization, antenna gain, radiation patterns, image theory, and frequency response.

In addition to the experiment procedures, this paper presents the design and characterization of Helical Beam (RHCP and LHCP) and …

Absorber Foam Characterization For Predicting Overall Anechoic Chamber Performance, Christopher R. Brito, Aloysius Aragon Lubiano, Newlyn Hui, Dean Y. Arakaki

Electrical Engineering

A new rectangular anechoic chamber (20’L x 10’W x 9’7”H) has been established at California Polytechnic State University (Cal Poly) through donations and financial support from industry and Cal Poly departments and programs. The chamber was designed and constructed by three graduate students as part of their thesis studies to explore and further their understanding of chamber design and antenna measurements. The chamber project has included RF absorber characterization, overall chamber performance assessment, and software development for the coordination of a positioner with a vector network analyzer.

This paper presents absorber characterization as a function of incidence angle and orientation …

Optical Filter Elements And Methods Of Making And Using Same, Michael A. Scobey, Lucien P. Ghislain, Dennis J. Derickson, Loren F. Stokes

Electrical Engineering

Optical filter elements and optical systems comprise optically mismatched etalons and optically mismatched stacked, optically coupled etalons that are directly optically coupled, at least one of the etalons or stacked, optically coupled etalons comprising first and second selectively transparent thin film mirror coatings on opposite surfaces of a bulk optic. The optically mismatched etalons can be configured to selectively pass single passbands. The disclosed optical systems optionally comprise other devices optically coupled to the optically mismatched etalons and optionally mismatched stacked, optically coupled etalons.

Structural Graph Matching With Polynomial Bounds On Memory And On Worst-Case Effort, Fred W. Depiero

Electrical Engineering

A new method of structural graph matching is introduced and compared against an existing method and against the maximum common subgraph. The method is approximate with polynomial bounds on both memory and on the worst-case compute effort. Methods work on arbitrary types of graphs and tests with strongly regular graphs are included. No node or edge colors are needed in the methods; the common subgraph is extracted based in structural comparisons only. Monte Carlo trials are benchmarked with 100% additional (clutter) nodes. Results are shown to be typically within 1-2 nodes of the maximum common subgraph. Over 7500 test trials …

Electromagnetic Crosstalk Penalty In Serial Fiber Optic Modules, Xiaomin Jin, Keith D. Lystad, Musoke H. Sendaula

Electrical Engineering

Electromagnetic crosstalk poses a serious problem within today S advanced serial communication modules. A major detrimental effect is the degradation of receiver sensitivity in the presence of crosstalk noise. The mitigation of crosstalk penalty becomes increasingly more challenging as data rates increase for higher throughput and as module sizes shrink for increased port density. This paper is a study of the primary sources of crosstalk penalty in a 2.5 GB/s serial fiber optic transceiver and a 10Gb/s serial fiber optic transponder. A novel method for quantifying crosstalk penalty by observing a receiver’s bit-error-ratio (BER) versus transmitter to receiver signal phase …

Efficient Orchestration Of Sub-Word Parallelism In Media Processors, John Y. Oliver, Venkatesh Akella, Frederic T. Chong

Electrical Engineering

Communication and multimedia applications with increased data rates and enhanced functionality continuously raise the bar for the computational requirements of future microprocessors. In order to meet these computational demands it is necessary to exploit sub-word parallelism efficiently. We propose to make sub-word data movement a first-class operation in microprocessor architectures by introducing a Sub-word Permutation Unit (SPU)in the execution pipeline. The SPU is evaluated in the context of the MMX media co-processor for the Intel Pentium architectures, but our results can be extended to any processor that supports sub-word parallelism. We find that the SPU all ws us to orchestrate …

Synchroscalar: A Multiple Clock Domain, Power-Aware, Tile-Based Embedded Processor, John Y. Oliver, Ravishankar Rao, Paul Sultana, Jedidiah Crandall, Erik Czernikowski, Leslie W. Jones, Iv, Diana Franklin, Venkatesh Akella, Frederic T. Chong

Electrical Engineering

We present Synchroscalar, a tile-based architecture for embedded processing that is designed to provide the flexibility of DSPs while approaching the power efficiency of ASICs. We achieve this goal by providing high parallelism and voltage scaling while minimizing control and communication costs. Specifically, Synchroscalar uses columns of processor tiles organized into statically-assigned frequency-voltage domains to minimize power consumption. Furthermore, while columns use SIMD control to minimize overhead, data-dependent computations can be supported by extremely flexible statically-scheduled communication between columns. We provide a detailed evaluation of Synchroscalar including SPICE simulation, wire and device models, synthesis of key components, cycle-level simulation, and …

One-Tap Wideband I/Q Compensation For Zero-If Filters, Peter Kiss, Vladimir I. Prodanov

Electrical Engineering

The I/Q imbalance is one of the performance bottlenecks in transceivers with stringent requirements imposed by applications such as 802.11a. The mismatch between the frequency responses of two analog low-pass filters, used, e.g., for channel selection in zero-IF receivers, makes this I/Q imbalance frequency dependent. Usually, frequency-dependent I/Q mismatch is estimated and corrected by adaptive techniques, which are complex to implement and may converge slowly due to noise. In this work, a simple, delay-based I/Q compensation scheme is proposed based on an extensive statistical analysis. Its digital implementation uses only two coefficients, which are tuned by a one-step two-tone error …

I/Q Imbalance Of Two-Path Ladder Filters, Peter Kiss, Vladimir I. Prodanov

Electrical Engineering

The frequency-(in)dependent I/Q imbalance of analog filters is a significant contributor to the tight noise budget of high-performance wireless applications, such as 802.11a wireless LANs. This paper proposes a “frequency-dependent” statistical I/Q-imbalance analysis method for two-path filters, which can be configured for both low-IF and zero-IF architectures. A 7-pole complex band-pass ladder filter is analyzed, and it shows large image rejection ratio (rms IMR > 43.7 dB for 3 σ). The same filter, but reconfigured as a pair of real low-pass filters, achieved about 13-dB less IMR. These results suggest a low-IF architectural choice to combat the I/Q imbalance of two-path …

A "Divide And Conquer" Technique For Implementing Wide Dynamic Range Continuous-Time Filters, Yorgos Palaskas, Yannis Tsividis, Vladimir I. Prodanov, Vito Boccuzzi

Electrical Engineering

This paper presents a technique for implementing analog filters with wide dynamic range and low power dissipation and chip area. The desired dynamic range of the filter is divided into subranges, each covered by a different filtering path optimized specifically for this subrange. This results in small admittance levels for the individual filtering paths and correspondingly small power dissipation and chip area. The system provides undisturbed output during range switching, contrary to conventional automatic gain control (AGC)/filter arrangements that generate disturbances every time the gain of the AGC changes. We also report on a low-noise highly linear CMOS transconductor useful …

Optically Coupled Etalons And Methods Of Making And Using Same, Michael A. Scobey, Lucien P. Ghislain, Dennis Derickson, Loren F. Stokes

Electrical Engineering

Optical elements comprise stacked, optically matched and optically coupled etalons, at least one of the optically coupled etalons comprising first and second selectively transparent thin film mirror coatings on opposite surfaces of a bulk optic. The bulk optic defines the cavity spacing of the etalon and may, for example be formed of a monolithic body of silica or other optically transparent glass diced from a glass wafer. The bulk optic may further comprise a wedge coating of progressively increasing thickness overlying the monolithic glass body and compensating for, or offsetting non-parallelism of the bulk optic. The bulk optic may further …