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This work proposes a microwave angular displacement sensor with wideband matching based on a wideband impedance transformer. According to the design requirement of the microstrip impedance transformer (load‐to‐source impedance of 250‐to‐50 Ω, centre frequency of 2.40 GHz) with Chebyshev frequency response, the proposed angular displacement sensor is explored for the high bandwidth sensitivity of 11.18 MHz/degree. [ABSTRACT FROM AUTHOR]

In this brief, the design methodology of microstrip impedance transformers with extreme (i.e., extremely high and extremely low) impedance transforming ratios is proposed by deploying the cross-shaped structure (CSS) configuration. The proposed impedance transformer can significantly eliminate the line width limitation of traditional quarter-wave impedance transformer and hence an extremely wide range of impedance transformation can be easily realized. At the same time, the impedance transformer provides a good frequency selectivity, especially in the narrowband regime. To demonstrate the outstanding performance of proposed CSS impedance transformer, two examples, with the load-to-source impedances of 2000-to-50 $\Omega $ and 5-to- $50~\Omega $ , respectively, are presented and prototyped. The measurement results are in good agreement with the simulated counterparts and hence, the outstanding performance of extreme impedance transforming ratios is validated. [ABSTRACT FROM AUTHOR]

In this paper, the design methodology of a microstrip angular displacement sensor based on an impedance transformer with a quasi-Chebyshev frequency response is proposed. This sensor with impedance transforming function can realize the angular displacement detection by bandwidth sensing, and matching sensing simultaneously. The insertion loss in stopband achieves 24.9 dB to 32.6 dB with an average bandwidth selectivity of 2.25 MHz/degree of the sensor centered at 2.4 GHz with two poles of 1.71 GHz and 2.81 GHz. Meanwhile, the average matching level of return loss for displacement sensitivity are 0.18 dB/degree and 0.15 dB/degree, respectively. It is the first time to apply an impedance transformer into the angular displacement sensor design for both bandwidth and matching level sensing among reviewed literatures. In this design, the load-to-source impedance transformation is designed for 250-to- $50~\Omega $ , and by adding a rotated stub on the proposed microstrip transformer, the sensing function is developed with angular displacement. [ABSTRACT FROM AUTHOR]

INTRODUCTION Intrapancreatic accessory spleen is an uncommon congenital abnormality of the spleen with no indication for surgical intervention. Among the few cases reported, IPAS coexisted with a normal spleen. We here report the first case of IPAS arising a couple years after splenectomy with the appearance of an endocrine tumor of the pancreas. PRESENTATION OF CASE A 62-year-old female presented with a one-week history of left upper quadrant discomfort. She had splenectomy for the treatment of hypersplenism caused by cirrhotic portal hypertension two years before this admission. Her physical examination was unremarkable and laboratory data was within the normal range. Both the ultrasonography and magnetic resonance image revealed a small oval-shaped mass in the tail of her pancreas with the diameter 2 cm or less. A distal pancreatectomy was performed for the suspection of malignant neuroendocrine tumor of the pancreas. An intrapancreatic accessory spleen was confirmed by the pathologic examination. DISCUSSION Intrapancreatic accessory spleen is one kind of congenital ectopic spleen without indication for operative intervention. We present the case to support that intrapancreatic accessory spleen may enlarge through a compensatory mechanism, and raise the awareness of this intrapacreatic entity to avoid unnecessary surgical operation. CONCLUSION IPAS should be highly considered as a differential diagnosis while the lesion is no more than 2.5 cm in diameter and/or other accessory spleens show around the splenic hilum. [ABSTRACT FROM AUTHOR]