Browsing by Author "Chang, Chih-Kai"

Now showing 1 - 4 of 4

5-6 GHz CMOS Low-Noise Direct Conversion Receiver Using a Differential RF VGA with a Differential Inductor Load
(2016)
Chang, Wei-Ling
;
Meng, Chinchun
;
Chang, Chih-Kai
;
Huang, Guo-Wei
;
電子工程學系及電子研究所
A low-noise low-power direct conversion receiver with a differential RF VGA is demonstrated using 0.18um CMOS technology. A topology that uses a differential inductor load for a differential RF VGA is employed for the single-to-differential conversion. Since the common-mode rejection ratio of a differential variable gain amplifier is increased by the mutual magnetic coupling in a differential inductor load, this work achieves noise floor less than 5 dB covering the 5-6 GHz band. Moreover, the conversion gain is around 50 dB and the total current consumption is 4.75 mA at 1.8 V supply voltage.
Analytical Noise Optimization of Single-/Dual-Band MOS LNAs With Substrate and Metal Loss Effects of Inductors
(2019-07-01)
Chang, Wei Ling
;
Meng, Chinchun
;
Ni, Jung-Hung
;
Ch, Kai-Chun
;
Chang, Chih-Kai
Analytical noise formulations and design optimization of single- and dual-band inductively source-degenerated MOS low-noise amplifiers (LNAs) with the substrate and metal loss effects of on-chip inductors are established in this paper. It reveals that the noise figures of both single-/dual-band LNAs degrade substantially under the consideration of the loss effects. However, by increasing the device size, the noise optimization methodology of simultaneous noise and input match for a single-band LNA still holds true with concern for the loss effects. For a dual-band LNA, analytical noise optimization for a balanced noise design is established for inductors with metal and substrate loss and indicates a larger device size. The substrate and metal loss effects of inductors can be mitigated using integrated passive device (IPD) process for the input match network. The demonstrated single-band 0.18-mu m MOS LNAs with and without IPD process show noise figures of 1.53 and 2.52 dB at 2.4 GHz, respectively. Subsequently, the implemented dual-band 0.18-mu m MOS LNAs with and without IPD process show noise figures of 1.6/2.6 and 3.25/4.1 dB at 2.4/5 GHz, respectively.
Ultrasensitivity of self-powered wireless triboelectric vibration sensor for operating in underwater environment based on surface functionalization of rice husks
(2019-06-01)
Lai, Sz-Nian
;
Chang, Chih-Kai
;
Yang, Cheng-Shiun
;
Su, Chun-Wei
;
Leu, Chyi-Ming
We demonstrate the self-powered wireless triboelectric vibration sensor as made from the naturally nanoporous SiO2 particles for allowing the detection of the vibrations and movement in the underwater environment. The nanoporous SiO2 particles are directly converted from the rice husks (referred to as RHsiO2), which exhibit strongly interacting surface hydroxyl groups. Through the enzymatic treatments, the surface potential of the RHsiO2 particles can be modulated to obtain either an extremely low or strongly high electronegativity. Specifically, by adding fluorinated groups using fluoroalkylsilane (FOTS) treatment to obtain RHsiO2-F, the charge density of the RHsiO2-F triboelectric nanogenerator (TENG) can be enhanced similar to 56.67-fold as compared to the untreated RHsiO2-TENG. The power density of the RHsiO2-F TENG is increased from 0.077 mWm(-2) to 261 mWm(-2). The RHsiO2-F particles are encapsulated in a quartz cube to fabricate a self-powered wireless sensor that can be stabilized for operating in an underwater environment at various temperatures. The theoretical calculation further demonstrates that the triboelectric potential is dramatically established between the surface functionalized RHsiO2-F particles and the quartz's surface. With porous nature of rice husks covered with nano-Si is of a high functionality for designing a new-type TENG which has a great potential to apply in the environmental monitoring.
V-band pHEMT Dual-Conversion Down-Converter With Schottky Diode RF Mixer and Analog Gilbert IF Mixer
(2014-01-01)
Chang, Wei-Ling
;
Meng, Chinchun
;
Chang, Chih-Kai
;
Huang, Guo-Wei
;
電機工程學系
A V-band dual-conversion down-converter with the Schottky-diode first conversion mixer and the analog Gilbert second conversion mixer is demonstrated using 0.15-mu m pseudomorphic high electron mobility transistor (pHEMT) technology. The diode mixer based on quarter-wavelength design methodology occupies a reasonable real estate at millimeter-wave frequency while the analog IF mixer has the size advantage at low microwave frequency. A trifilar transformer is employed in the first mixer to have balanced RF/LO/IF signals for the anti-parallel diode-pairs while a Marchand balance converts the RF signal into the balanced one. Analog I/Q Gilbert mixers driven by the poly-phase filter in the LO port achieve precise I/Q IF output. As a result, this work achieves a wideband conversion gain around -1 dB from 54-64 GHz, -5 dBm of IP1dB, and 6 dBm of IIP3.