Magnetic properties of nanoparticle composites, consisting of aligned ferromagnetic nanoparticles embedded in a nonmagnetic matrix, have been determined using a model based on phenomenological approaches. Input materials parameters for this model include the saturation magnetization (M s ), the crystal anisotropy field (H k ), a damping parameter ͑␣͒ that describes the magnetic losses in the particles, and the conductivity ͑͒ of the particles; all particles are assumed to have identical properties. Control of the physical characteristics of the composite system-such as the particle size, shape, volume fraction, and orientation-is necessary in order to achieve optimal magnetic properties ͑e.g., the magnetic permeability͒ at GHz frequencies. The degree to which the physical attributes need to be controlled has been determined by analysis of the ferromagnetic resonance ͑FMR͒ and eddy current losses at varying particle volume fractions. Composites with approximately spherical particles with radii smaller than 100 nm ͑for the materials parameters chosen here͒, packed to achieve a thin film geometry ͑with the easy magnetization axes of all particles aligned parallel to each other and to the surface of the thin film͒ are expected to have low eddy current losses, and optimal magnetic permeability and FMR behavior.

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A phenomenological model of magnetic nanoparticle composites consisting of ideal lossless particles with identical properties embedded in a non-magnetic matrix has been developed. The input material parameter for this model include the saturation magnetization (M s ) and the crystal anisotropy field (H k ) of the particles. The relationships between key magnetic properties like the low frequency effective permeability and the FMR frequency, and the material and physical attributes (such as shape, volume fraction, and packing type) of the particles have been identified using an iterative extension of the Bruggeman effective medium theory.

Skyrocketing growth in the cellular personal communications services (PCS) sector has fueled the needs for higher density, more functionality, and greater performance on both handset and basestations. Third generation wireless standards, which require hardware upgrades, loom on the horizon. RF component suppliers are scrambling to find solutions at the IC, package, and PCB levels to meet these challenges. RF module packaging is considered as one of the low cost solutions to the future wireless products. One of the critical design needs for RF interconnects is to understand the electrical performance of wire bond (the RF interconnect of choice) at and above frequency of interest, and to determine the performance limit for the wire bond chip-to-substrate interconnect. The availability of design kit or library would result in a substantial reduction in design cycle times. Using wire bond as example, this paper illustrates the developmental stages that turn electromagnetic characteristics of a physical structure into design library. Fullwave simulation using Ansoft HFSS and compact models extraction using optimization tool for wire bond will be shown, followed by in-depth discussions of wire bond parameterized models. Validation of parameterized model by measurement will be presented. IntroductionRF module packaging has many advantages: favorable pricing power being the most important one, as opposed to cost-based pricing at the sum of the individual ICs and embedded passives costs. The module packaging can also benefit the system integrators who are less skillful in RF design and skills. This ease of use leads to proliferation of RF module demands. Design tools or libraries for module are one of the critical paths that enable a full adoption of the module technology.In this paper, the parameterized electrical compact (RLC) models of wire bonds (the RF interconnect of choice) are shown. Since interconnects are relatively independent of the substrate of choice, development of interconnect models need not be repeated as substrate of choice changes. Since LTCC allows an easy implementation of different die height (or thickness) using cavity, it is used in wire bond interconnect models development. Using mainly single wire bonds as example, the design tool development methodology is illustrated. First, the design space and Design of Experiment (DOE) for wire bonds are described, followed by Ansoft