Chun-Chi Su

A 6:1 Unequal Wilkinson Power Divider with EBG CPW

A 6 : 1 unequal Wilkinson power divider that combines the advantages of a coplanar waveguide with an electromagnetic bandgap (EBG CPW) and microstrip line structures suitable for a PCB circuit design is proposed. The highly characteristic impedance transmission line (TL) is realized by employing the proposed EBG CPW structure, which is difficultly achieved using the conventional microstrip line or CPW due to printed circuit board (PCB) process limitations. The proposed EBG structure enables the CPW line to have a very high characteristic impedance of over 207 Ω. The fabricated 6 : 1 power divider delivers excellent matching and isolation performances with more than 34 dB at 1.5GHz. It also has exact dividing ratios of 8.46 dB and 0.7 dB at two output ports, respectively.

A COMPACT BALUN BASED ON MICROSTRIP EBG CELL AND INTERDIGITAL CAPACITOR

A novel compact balun (balanced-to-unbalanced) that consists of a low-pass network served by a microstrip electromagnetic bandgap (EBG) cell and a high-pass …-network formed with an interdigital capacitor is presented. This proposed approach can efiectively operate the compact balun without the use of ‚=4 microstrip lines to reduce the circuit area over 50% compared to the conventional Marchand balun. The core dimension of the compact balun is 0:74cm£0:7cm. The planar structure enables an e-cient circuit design in printed circuit boards (PCB) without using any bonding wires, defected ground structures (DGS), or surface mounted devices (SMD). A compact balun operating in the 3GHz band has been implemented in a FR-4 PCB. From the measured results, the return loss of the input port is better than 15dB over the band from 2.6 to 4GHz. The amplitude and phase imbalances are less than 1.4dB and 3 - with the 20% operational bandwidth ranging from 2.7 to 3.3GHz, respectively.

The Miniature Frequency Doubler Using Compensated Capacitive Line in Balun

A compact balanced frequency MMIC doubler using compensated capacitive line in Marchand balun is proposed. With multi-coupled lines technology, the balun is applied to a balanced doubler successfully. Compared with the conventional Marchand balun, more than 55% reduction in the length of coupled line can be achieved. Implemented by a PHEMT process, the compact monolithic balanced frequency doubler with better performance can be obtained. An operation bandwidth from 20 to 44GHz with the best conversion loss of 8.4dB at 25GHz can be achieved. In addition, the fundamental frequency suppression is better than 28.9dB, and the chip dimension is as small as 0:41 £ 0:68mm 2 .