A. B. M. H. Rashid

High transmission gain integrated antenna on extremely high resistivity Si for ULSI wireless interconnect

We have demonstrated the highest transmission gain integrated dipole antenna on Si reported so far, to use as an integrated antenna for the purpose of ULSI on-chip wireless interconnection. A 2-mm long and 10-/spl mu/m wide dipole antenna pair at a distance of 1 cm shows a transmission gain of -36.5 dB at 18 GHz, which is 20 dB higher than the previously reported gain. This large increase in gain is achieved by proton implantation on the Si substrate, which increased the resistivity from 10 /spl Omega/-cm to 0.1 M/spl Omega/-cm. It is also found that transmission gain can be maximized for a given resistivity by optimizing the Si substrate thickness or by inserting a low-k dielectric layer below the substrate.

Characteristics of Integrated Antenna on Si for On-Chip Wireless Interconnect

We have performed the detailed characterization of small size integrated dipole antenna on Si for use in on-chip wireless interconnection and compared the measured characteristics with results obtained by 3-D finite element simulation. Basic characteristics such as the effects of antenna length, distance and rotation angle on the transmission gain of the integrated antenna are examined. The measured transmission gain of approximately -54 dB at a distance of 1 cm for a 0.02 mm2 dipole antenna at 20 GHz showed the feasibility of using the integrated dipole antenna for wireless clock distribution in future ultra LSI (ULSI) chips at frequencies of ~20 GHz or higher. We have also shown that it is possible to minimize any reduction in transmission gain due to the interference from the local interconnect metal lines by choosing the proper layout.

FPGA implementation of Real Time acoustic noise suppression by Spectral Subtraction using Dynamic Moving Average Method

The Paper presents the outlines of the Field Programmable Gate Array (FPGA) implementation of Real Time speech enhancement by Spectral Subtraction of acoustic noise using Dynamic Moving Average Method. It describes an stand alone algorithm for Speech Enhancement and presents a architecture for the implementation. The traditional Spectral Subtraction method can only suppress stationary acoustic noise from speech by subtracting the spectral noise bias calculated during non-speech activity, while adding the unique option of dynamic moving averaging to it, it can now periodically upgrade the estimation and cope up with changes in noise level. Signal to Noise Ratio (SNR) has been tested at different noisy environment and the improvement in SNR certifies the effectiveness of the algorithm. The FPGA implementation presented in this paper, works on streaming speech signals and can be used in factories, bus terminals, Cellular Phones, or in outdoor conferences where a large number of people have gathered. The Table in the Experimental Result section consolidates our claim of optimum resouce usage.

Effect of silicon substrate on the transmission characteristics of integrated antenna

The basic characteristics of integrated dipole antennas on a Si substrate for use in on-chip wireless interconnects have been studied. 2 mm long and 10 /spl mu/m wide integrated dipole antennas were fabricated on a Si substrate with a resistivity of 10 /spl Omega/-cm. and the transmission gain of the antenna was 38 dB at 20 GHz. The transmission gain could be improved by use of high resistivity Si substrates greater than 100 /spl Omega/-cm.

Detection and localization of faults in analog integrated circuits by utilizing the combined effect of output voltage gain and phase variation with frequency

In this paper, we have introduced a new technique based on simultaneous analysis of output voltage gain vs. frequency and phase vs. frequency for fault testing of analog integrated circuits. An Automated Test Frequency Generation method is demonstrated here to select minimum number of test frequencies as stimuli. The introduced technique is applied to three benchmark circuits and the obtained results are then compared to the results from gain vs. frequency and phase vs. frequency analysis methods. From the comparison, the proposed technique is found to be superior over the gain technique in detection and localization of faults. Finally, a method for identification and localization of faults by clustering is exhibited, which utilizes our proposed technique for better performance.

Crosstalk isolation of monopole integrated antenna on Si for ULSI wireless interconnect

Crosstalks on local interconnect metal lines at high frequency have been evaluated for wireless interconnect on Si using monopole integrated antenna. For an antenna of length 3 mm, the maximum value of crosstalk on a victim line of same length and separated by a distance of 10 /spl mu/m was found to be -18 dB at 9 GHz. Large reduction in crosstalk is possible by operating the antenna slightly off the resonance point.

Design of a wideband delay element for transmitted reference UWB receivers

The transmitted reference ultra-wideband (TR-UWB) scheme has generated considerable interest in the field of UWB radio and on-chip wireless interconnect systems. This paper presents a wideband delay element (WBDE) which is a major design concern for TR-UWB transceivers and introduces a novel WBDE architecture that eliminates the need for dual bipolar power supplies. A very wide range of delays of monotonic nature (100–1000ps) can be achieved by varying the dimensions of the transistors, the power supply voltage, the shunt capacitances and the number of stages in the delay chain. The WBDE, designed using IBM® 90nm CMOS technology, would make the circuit implementation of TR-UWB schemes realizable.

UWB microwave imaging via modified beamforming for early detection of breast cancer

Ultra-wideband (UWB) microwave imaging is a promising technique for detecting early stage breast cancer, which exploits the significant contrast in dielectric properties between normal and malignant breast tissues. In this paper, we have proposed a new modified compensation method and beamforming technique for microwave imaging. We used a three dimensional (3-D) Finite Integration Technique (FIT) based breast model, with normal breast tissue, supported on a layer of chest muscle and covered by a thin layer of skin. A small sized (1 mm diameter) tumor is placed within the breast tissue layer. A pair of rounded-edge bow-tie antennas at crossed position is used for transmitting and receiving microwave signals. This antenna pair is then placed at different positions over the breast surface and the incident and backscattered signal at each position are stored. Backscatters are then processed to eliminate artifacts. Finally they are passed through the beamformer and an image is formed. The beamformer is designed with adaptive weighting to compensate both propagation attenuation and lossy medium effect. Despite using the traditional delay-and-sum approach, new delay-and-product technique is used in beamforming. This modified beamforming approach is shown to outperform its previous counterparts in terms of resolution and sensitivity.

Optimization of VLSI architectures for DTW

In data mining and time series recognition applications Dynamic Time Warping (DTW) is a very popular method. It can produce accurate results provided its originality is preserved. But its lethargic nature has been inspiring development of its hardware based acceleration methods. In this paper, four novel VLSI architectures for performing DTW are proposed and compared. The comparison reflects achievement of significant conclusions specifically for performance critical and memory constraint applications.

A 200PS differential CMOS delay element for 10 GHz ultra wideband wireless receivers

Design of a novel selective band delay element and its performance gain over nominal low pass LC ladder based delay element is demonstrated. The delay element uses three 2nd order all pass filter as its core element and achieves a delay of 200 ± 10 ps within 6.8 GHz to 12.9 GHz range. The circuit is implemented using 130 nm RF CMOS technology. Total area of the circuit is 0.88mm × 0.86mm without bondpad and 0.88mm × 1.06mm with bondpad. The circuit uses only passive elements, thus there is no static power consumption. Maximum dynamic power consumption is found to be 6μW.