An ultra-broad-band reflection-type phase shifter is proposed. Theoretically, the proposed phase shifter has frequency-independent characteristics in the case of 180 phase shift. The phase shifter is composed of a 3-dB hybrid coupler and a pair of novel reflective terminating circuits. The reflective terminating circuit switches two states of series and parallel LC circuits. Using an ideal circuit model without parasitic circuit elements, we have derived the determining condition of frequency independence of circuit elements. Extending the concept, we can also obtain a broad-band phase shifter for other phase difference as well. In this case, for a given phase difference and an operating frequency, we also derive a condition to obtain minimum variation of phase difference around the operating frequency. This enables the broad-band characteristics for arbitrary phase difference. The fabricated 180 reflective terminating circuit monolithic microwave integrated circuit (MMIC) has achieved a phase difference of 183 3 over 0.5-30 GHz. The 180 phase-shifter MMIC has demonstrated a phase shift of 187 7 over 0.5-20 GHz. The 90 reflective terminating circuit MMIC has performed a phase difference of 93 7 over 4-12 GHz.
Although pencil injury is a common occurrence, only six cases of so-called pencil-core granuloma have been reported. All of these granulomas were relatively small, and most of them simulated malignant melanoma. We report a giant pencil-core granuloma that developed on a patient's right palm. Its gross appearance was quite different from that of other cases previously reported; it was much larger and resembled a hemangioma.
An innovation in the preparation of the vascular pedicle of the free radial forearm flap is presented. While the radial artery is commonly used as the arterial pedicle of the flap, either the cutaneous venous system or the radial comitant vein (deep venous system) is used as the venous pedicle. The perforating vein communicates between these two venous systems at the cubital fossa, and we confirmed its presence in all but one of more than 180 cases. When the vascular pedicle is dissected proximally to the perforating vein contained in the flap, the venous drainage of both the deep and cutaneous systems can be restored by anastomosis of only one vein: the cutaneous or the radial comitant vein. On the other hand, the flap can be raised with the radial vessels (without the cutaneous vein) at the start of surgery, and a large caliber cutaneous vein, such as the median cubital, the cephalic, or the basilic, can be used for anastomosis in cases where the cutaneous veins in the distal forearm are too thin, or where the radial comitant vein is composed of two thin separated veins. We believe that preserving the perforating vein would make the forearm flap more reliable and more convenient in reconstructive surgery.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.