PCS band and AMPS band antennas were mounted on the dashboard of an automobile. Antenna patterns toward the rear of the vehicle were measured as the antennas were tilted from the horizontal position. Results showed that for the PCS band antenna, the beam pointing angle significantly affected the frequency averaged patterns, while for the AMPS band antenna the frequency averaged patterns were minimally impacted by the antenna tilt.

A procedure is presented to simulate the complete automobile radio system, from antenna to speaker. The method involves generating reduced order models of all relevant components and interactions, which are then linked together in a time-domain system solver. To illustrate the usefulness of this simulation capability in vehicle-level system design a novel algorithm for automated computer rating of automobile audio tracks is developed. The algorithm uses wavelet and Fourier decompositions for automated computer rating of audio quality. The algorithm developed is validated by comparing its output to a study using human subjects to score recorded audio tracks

This paper describes a novel, low-profile antenna for the satellite digital audio radio service. The antenna consists of a thin cavity with a pair of crossed slots having unequal length. Both slots are fed by a single-probe-type feed, resulting in a simple low-cost structure. This antenna is left-hand circularly polarized toward the sky for satellite reception, and vertically polarizated toward the horizon for terrestrial reception. The result is a low-profile antenna that can receive simultaneously from both satellite broadcasters and terrestrial repeaters, and can be built using low-cost printed circuit fabrication methods.

Results of a three-dimensional electromagnetic (3D EM) simulation of a generic automobile is presented. Full wave MoM based 3D EM code was applied to compute the normalized received power between a transmitter and a receiver of a tire pressure monitor system (TPMS) on a simplified model of an automobile. An overview of the procedure used to calculate the TPMS normalized received power using the EM modeling procedure is provided.

Two-way wireless communication subsystems (WCS) for voice and data applications will play a central role in future vehicular telematics systems. We discuss some of the design and hardware implementation choices for such wireless communication systems in this paper. Specifically, the impact of wireless communications infrastructure evolution in the U.S. and advances in enabling hardware technologies on the design choices of WCS are addressed. The paper also presents a radio test-bed based on the CDMA2K 1xRTT communication standard, implemented using an advanced system simulation tool. The motivation behind development of the test-bed is to assess the performance of 'direct IF digitization architecture' for the proposed WCS in various wireless channels for different vehicle velocities. The simulation results will ascertain whether the design is suitable for future vehicular telematics systems.

Our previous work is presented on diversity antenna experiments in the 2.3 GHz band, specifically for applications in the automotive environment. We describe the case of two-element position diversity, and we study the effects of the antenna positions on the amount of diversity gain. The presentation consists primarily of measurement data on a moving vehicle, with software post-processing to determine the effects of diversity combining. We present several diversity combining schemes, and describe a switched diversity circuit that we have built to address one of these schemes. An in-house developed SPDT MEMS switch, which has desirable insertion loss and isolation characteristics for the diversity switch, is shown. Also, a discussion on using a switch for the switched diversity antenna is included.

A four-sector diversity antenna on a high-impedance ground plane has been built for use in vehicular communications. The high-impedance ground plane suppresses the propagation of surface currents, and allows the antenna to lie adjacent to the metal exterior of the vehicle. Switched-beam diversity is used to mitigate interference.

Silicon waferboard technology based on etched and deposited passive-alignment features has been applied to the fabrication of optoelectronic transmitter and receiver arrays for rf applications. Using silicon waferboards, we have aligned both 1 by 4 buried-heterostructure laser arrays and 1 by 4 PIN photodetector arrays to optical fiber ribbons. Besides serving as mechanical carriers and alignment guides, the silicon wafers can also be used as rf or microwave substrates. We introduce rf-optoelectronic receiver arrays based on such enhanced silicon waferboards.

Hybrid integration utilizing silicon waferboard as a platform for mounting discrete and array components, is an attractive alternative to using conventional sub-mounted devices when building low-cost, high-performance, multichannel optical transmitter and receiver modules. Silicon substrates are extremely versadle as a platform material for the following reasons: 1) both multimode and single mode fiber can be mounted into v-grooves etched into the silicon surface; 2) alignment fiduciaU formed on the silicon surface, provide a registration feature for optoelectronic devices such as emitters and detectors; 3) signal traces can be defined using conventional photo-lithography techniques on a common silicon substrate; one that carries the components as well as the optical fibers; and 4), heat can be efficiently transported away from the active devices mounted on the silicon surface through die silicon platform.

This paper describes the development of laser transmitter arrays for analog optoelectronic link applications up to 2 GHz. These modules have been developed in an attempt to utilize passive assembly and alignment operations for the purpose of reducing costs. To this end, silicon waferboard integration platforms and semiconductor laser arrays have been fabricated with special alignment features that allow passive assembly of flip-chip laser arrays to single-mode optical fiber arrays.

We describe the design of single frequency array transmitters and their application in RF-photonic systems. In addition, we present an array-based packaging technology that is based on passive-alignment with Si-waferboards.

This paper describes the packaging challenges associated with array-based transmitters and receivers used for analog fiber-optic links. The optoelectronic modules are being developed under an ARPA Analog Optoelectronic Module TRP. The paper will focus on the development of optoelectronic array modules using silicon waferboard technology for application to personal communication systems

An intraframe block coding scheme which is devoted to of using interblock redundancy and reducing the block effect is proposed. The scheme is based upon a combination of a nonlinear interpolation with transform and vector quantization techniques. Interblock redundancy is removed by extracting a pixel from each block as a common seed to interpolate the rest of the pixels of the neighboring blocks. The estimation error signals are reduced by nonlinear interpolation, which often results in no further processing requirements for some blocks. This saving compensates for the cost of transmitting the overhead of the estimation parameters.

We measured the loss of bend resistant fibres at small bend radii of 1 to 5 mm. A spectral interpolation technique was used to measure the bend loss over 1300–1600 nm range. Fibres with 7.3μm mode field diameter at 1550 nm show <0.4dB/cm at 2 mm radius.

We demonstrate a practical four-port flip chip end fire coupler useful for providing efficient coupling between single-mode fibers and Ti-diffused LiNbO3 channel waveguides. Channel waveguide ends were prepared for coupling by cleavage. With a configuration suitable for multiple fiber coupling, coupling efficiencies up to 47% have been measured for TM polarization. Using micropositioners to align single input and output fibers with respect to the channel waveguide, end fire coupling efficiency was 58% (TM). The effect of waveguide mode mismatch and misalignment on coupling efficiency is investigated. We also observe double refraction and leaky mode propagation with TE polarized input to LiNbO3 channel waveguides running perpendicular to the cleavage plane. With suitably prepared channel waveguides on LiTaO3, these effects are small or absent.

The use of any form of evanescent coupler to couple between a high index waveguide system and a low index waveguide system requires the introduction of a buffer layer to shield the evanescent coupling region from the high index substrate. For example to use a tapered velocity coupler to couple between a high index indiffused electro-optical waveguide and a low index single mode glass fiber as shown in Fig. 1, requires that the power in the electrooptical waveguide be lifted off the substrate over a low index buffer layer before the evanescent coupling region is introduced. A buffer layer with an index lower than the effective index of the fiber mode is necessary to prevent phase matched evanescent coupling between the guided mode of the fiber and the substrate modes of the electrooptical crystal.

We report a practical approach to the positioning of a number of single-mode fibres for endfire coupling to channel waveguides. Boivin's approach has been extended to a flip-chip configuration which permits its use with substrates other than silicon.