PurposeThis paper presents a novel mesoscale RF (mRF) relay that integrates advanced high resolution stereolithography (SL) and micro wire electro discharge machining (μEDM) technologies. Methods and infrastructure for reliable batch assembly of electromechanical actuators and structural parts less than 5 mm3 in volume are described. Switches made using these techniques are expected to have greater power handling capability relative to current micro RF relay products.Design/methodology/approachThe conjecture is that the integration of SL and similar rapid additive manufacturing with other mesofabrication technologies can yield innovative miniature products with novel capabilities. A series of mRF prototypes consisting of a contact mechanism and actuator with return spring were fabricated assembled, inspected, and characterized for electromechanical performance. Characterization results led to specific conclusions regarding capabilities of the mRF product, and the integrated manufacturing technique.FindingsThe microassembly apparatus and epoxy‐based fastening system led to durable prototypes within 4 h (excluding a 16‐24 h cure cycle). Relay stroke ranged from 560 to 1,650 μm indicating a relative assembly accuracy of 90 percent. Prototypes demonstrated insertion loss of 1.3 dB at 100 MHz and isolation of better than 30 dB through 300 MHz.Research limitations/implicationsResults indicated that fully functional and robust mesoscale relays are possible using integrated manufacturing with SL. However, prototypes exhibited high contact resistance and lacked assembly precision in the context of contact mechanism stroke. Opportunities exist to reduce contact resistance and switching time.Practical implicationsThe research provides a practical new product application for integrated mesoscale rapid manufacturing.Originality/valueThis work represents one of the first examples of a mesoscale relay rapidly manufactured with a combination of μEDM and SL components.
Correlation is often used as an approach to automated pattern recognition. Generally, correlation provides a measure of the similarity between a reference template and regions of an input image. This measure is also highly dependent on intensity variations in the input image, thereby hindering the performance of simple peak detection decision algorithms. Normalization can be used to achieve intensity invariance of correlation results. This paper will address some aspects of normalization for a few filter types. For matched filters, the CauchySchwarz inequality provides an effective method by taking into account the energy of the input image within the spatial region of support of the template. For many other types of filters being considered for pattern recognition applications, the regions of support are not always limited to the area occupied by the template pattern. This excessive support can produce undesirable effects in the correlation results whether normalized or not.Benefits of normalized correlation such as intensity invariance and resistance to high energy clutter will be discussed along with some problems associated with regions of support. Matched filters, phase-only filters, and binary phase-only filters will be investigated. Computer simulations of several cases will be used to demonstrate results.
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