Ping-Chun Yeh

Compact 28-GHz subharmonically pumped resistive mixer MMIC using a lumped-element high-pass/band-pass balun

This work reports a novel lump-element balun for use in a miniature monolithic subharmonically pumped resistive mixer (SPRM) microwave monolithic integrated circuit. The proposed balun is simply analogous to the traditional Marchand balun. The coupled transmission lines are replaced by lump elements, significantly reducing the size of the balun. This balun requires no complicated three-dimensional electromagnetic simulations, multilayers or suspended substrate techniques; therefore, the design parameters are easily calculated. A 2.4-GHz balun is demonstrated using printed circuit board technology. The measurements show that the outputs of balun with high-pass and band-pass responses, a 1-dB gain balance, and a 5/spl deg/ phase balance from 1.7 to 2.45 GHz. The balun was then applied in the design of a 28-GHz monolithic SPRM. The measured conversion loss of the mixer was less than 11dB at a radio frequency (RF) bandwidth of 27.5-28.5 GHz at a fixed 1 GHz IF, a local oscillator (LO)-RF isolation of over 35 dB, and a 1-dB compression point higher than 9 dBm. The chip area of the mixer is less than 2.0 mm/sup 2/.

Effects of Mechanical Uniaxial Stress on SiGe HBT Characteristics

In this work, we investigate the characteristics of collector current (I_C) and breakdown voltage (BV_CEO) of SiGe HBTs under the mechanical uniaxial stress by a four-point bending apparatus. DeltaI_c and DeltaBV_CEO is found to be strain-polarity dependent, and there is a trade-off between DeltaI _c and DeltaBV_CEO at the same stress condition

High Performance Spiral Inductor on Deep-Trench-Mesh Silicon Substrate

This letter presented the octagonal spiral inductors on deep-trench-mesh substrate which obtained a high self resonant frequency (f_res) and high peak quality factor (Q_peak) in a 0.35-mum 3P3M SiGe BiCMOS process. The main advantages of the deep-trench-mesh structure were twofold: 1) deep-trench-mesh pattern decreased capacitive coupling and increased f_res by 10% compared to a conventional structure and 2) decreased resistive losses and increased Q_peak around 15%. The overall figure-of-merit was improved by 28% while dealing with Q_peak, f_res, and chip area. Meanwhile, a broad Q_peak frequency response was found in deep-trench-mesh inductors

An Experimental Study on High-Frequency Substrate Noise Isolation in BiCMOS Technology

In this letter, four substrate noise isolation structures in standard 0.18-mum SiGe bipolar CMOS technology were investigated using S-parameter measurements. The experimental and simulated results on different isolation structures, such as triple-well p-n junction isolated walls, deep trench isolation, and double P+ guard-ring structures, are presented. Each element in the equivalent circuits has been calculated or fitted based on the parasitic resistance, capacitance, and physical dimensions using the device simulator MEDICI and the measured results of the test patterns. The proposed structure B significantly reduced substrate noise below -70 dB up to 20 GHz. The proposed structure C with an extra triple-well junction achieved the best isolation at the lower frequency range, in which |S21| was less than -71 dB from 50 MHz to 10.05 GHz, and -56 dB from 10.05 to 20.05 GHz. The measured results showed an excellent agreement with the calculations. Structure B is good enough and is recommended for a general-purpose RF circuit design, whereas structure C can be used in a highly sensitive RF circuit block below 10 GHz.

A 1.8-V monolithic SiGe HBT power amplifier with a novel proposed linearizing bias circuit

In this work, we report a linearization technique by using an on-chip linearizer. The linearizer consists of a SiGe heterojunction bipolar transistors active bias circuit with a MOSFET feedback junction capacitor, which significantly improves the gain compression and phase distortion without additional dc consumption. The proposed circuit topology finds extensive applications in high efficiency and linearity power amplifier design. The power amplifier is implemented by using TSMC 0.18 mum SiGe HBT technology. The compact VBIC model of SiGe HBT was successfully established for the circuit design, and then a 2 GHz power amplifier was designed for demonstrating the circuit performances. The HBT power amplifier exhibits an output power over 20 dBm with a power-added efficiency higher than 42.4% under 1.8 volt operation

Geometry Effect on SiGe Heterojunction Bipolar Transistor Unit Cell for 1 W High-Efficiency RF Power Amplifier Applications

The effect of geometry on the RF power performance of silicon–germanium heterojunction bipolar transistor (SiGe HBT) unit cells is investigated using various emitter finger spacing (S). Two unit cells, namely, HBT-1 and HBT-2 with the same emitter area of 8×0.6×10 µm3 but with different S values are thoroughly discussed. The S values of HBT-1 and an HBT-2 are 2 and 5 µm, respectively. The obtained measurements, including DC characteristics and small- and large-signal performance characteristics of high-breakdown SiGe HBT unit cells, are presented. The HBT-1 in class-AB operations at 2.4 GHz achieves an output 1 dB compression point (OP1dB) of 16.0 dBm, a maximum output power of 17.4 dBm, and a peak-power added efficiency (PAE) of 59.1%. Under the same testing conditions, HBT-2 achieves an OP1dB of 19.6 dBm, a maximum output power of 20.6 dBm, and a PAE of 64.5%. HBT-2 yields significant improvements in all power performance parameters compared with HBT-1, such as 3.6 dB in an OP1dB, a maximum output power of 3.2 dB, a PAE of 5.4%, and an improvement in the power performance figure of merit (FOM) of approximately 50%, which is attributed to the fact that HBT-2 has a lower thermal effect than HBT-1. The thermal effect affects both DC and output power characteristics. A 1 W power device fabricated by combining eight HBT-2 unit cells achieves a power gain of 14.5 dB and a maximum PAE (PAEmax) of 75% in a class-AB operation at 2.4 GHz. The power density is calculated to be up to 2.6 mW/µm2. These results demonstrate that SiGe HBT technology has great potential for high-power amplifier applications.

An evaluation of SiGe/Si HBT high efficiency power amplifiers for wide dynamic power control range application

This work investigates three power amplifier circuit architectures for wide dynamic power control range application. These circuit architectures are the adaptive bias, classical Doherty and extended Doherty amplifiers which are implemented using TSMC 0.35 /spl mu/m SiGe HBT technology. These power amplifiers were designed in 2 GHz band over 70 dB power control range. In order to compare the average power added efficiency (PAE/sub AVG/) of the full power control range in different architectures, all amplifiers were intentionally designed with the same device size and therefore obtained the same maximum output power. The PAE/sub AVG/ of the adaptive bias amplifier is only 0.65% in the condition of 70 dB power control range. The classical Doherty amplifier and four-ways extended Doherty amplifiers have been improved up to 2.04% and 3.78%, respectively. In contrast to the adaptive bias amplifier, the PAE/sub AVG/ of classical Doherty and four-ways extended Doherty amplifier have remarkably been improved of 314% and 581%, respectively.