| Summary: | 碩士 === 國立成功大學 === 微電子工程研究所碩博士班 === 95 === A 2.4GHz planar power divider for harmonics suppression is investigated. The microstrip electromagnetic-bandgap (EBG) cell is used to suppress the nth harmonics and to reduce the length of a quarter-wave line over 30% as compared to the conventional power dividers. The planar structure enables an easy circuit design and implementation in printed circuit boards. From the measured results, a 32.5 dB suppression for the 3rd harmonic and a 12 dB suppression for the 5th harmonic can be achieved. While maintaining the characteristics of a conventional Wilkinson power divider, the two equivalent insertion losses are 3.4dB.
A low voltage, ultra wide band CMOS folded mixer for Ku~K-band applications is proposed. The concept of this design is based on the Gilbert mixer structure, using high pass wideband folded architecture to overcome the disadvantage of narrow band application in traditional folded structure, and increasing the bandwidth by integrating two spiral baluns into the chip. For the reason of using wideband folded structure, the conversion gain of 9 4dB from 10 to 25 GHz is derived, and port-to-port isolations are all better than 47dB.
With suitable diode arrangements and the use of spiral balun, a doubly balanced sub-harmonic diode ring mixer bandwidth enhancement has been achieved. The conversion loss is less than 13dB from 21 to 30GHz, and the isolations are larger than 34dB between LO-RF, RF-IF, and LO-IF ports. The chip size is reduced to 1×1mm2 as a result of IF signal can be extracted directly from RF balun circuit.
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