Browsing by Author "CHIANG, YC"

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AN ULTRA-LOW COST AND MINIATURE 950-2050 MHZ GAAS MMIC DOWNCONVERTER .1. DESIGN APPROACH AND SIMULATION
(1995-05-01)
HSIEH, TH
;
WANG, H
;
WANG, TH
;
CHEN, TH
;
CHIANG, YC
A miniature ultra low cost 950-2050 MHz GaAs MMIC downconverter has been designed for satellite TV application using a 1-mu m gate-length, ion-implanted GaAs MESFET foundry process. To accurately predict circuit performances, both linear and nonlinear equivalent circuit models have been developed to characterize the RF and de behaviors of device. Modeled simulation results show correspondence with the experimental data. This monolithic downconverter is comprised of an RF LNA, a dual-gate MESFET mixer, an IF variable gain amplifies and a varactor tuned oscillator. The primary design specifications are (1) 50-dB conversion gain, (2) 4-dB noise figure, (3) more than 40-dB gain controllable range, and (4) 50-dBc third-order intermodulation distortion. The chip size is 1.4 x 1.5 x 0.18 mm(3). It is encapsulated in a standard low cost mm plastic package. Moreover, this downconverter IC is promising for miniaturization and cost-reduction of a DBS receiver The detailed measured characteristics will be presented in part-II of this paper.
DESIGN OF A 3-DIMENSIONAL GAP-COUPLED SUSPENDED SUBSTRATE STRIPLINE BANDPASS FILTER
(1992-08-01)
CHIANG, YC
;
TZUANG, CKC
;
SU, S
;
交大名義發表
;
電信工程研究所
A three-dimensional gap-coupled suspended substrate stripline (SSS) bandpass filter, based on the modified configuration of the classic end-coupled filter, is presented. it consists of printed half-wavelength resonators placed on the same and/or the opposite sides of the suspended substrate. These resonators orient themselves in arbitrary directions. Such an arrangment makes the new filter highly flexible to interface with other microwave subcircuit modules. The filter is constructed in a bent channelised housing that suppresses any possibility of exciting higher-order modes, except the dominant quasi-TEM mode of propagation. Consequently, the channelised filter is free from any coupling between itself and other microwave circuit components within the system. Two look-up tables, derived from a variational three-dimensional quasi-TEM spectral-domain analysis of the discontinuity problems associated with the adjacent gap-coupled resonators, are incorporated into the computer-aided design of the new filter. The de-embedded discontinuity parameters are validated by comparing them with those obtained by experiment and full-wave approaches for the microstrip open-end and the SSS end-coupled problems, respectively. The measured results for the experimental 21-22 GHz bandpass filter agree very well with the theoretic predictions considering the conductor losses (5.57 x 10(-3) dB/mm) of the SSS. It has less than 1.4 dB insertion loss and greater than 10 dB return loss in the passband.