Future cable television (CATV) and satellite-television receiver systems require the development of wideband power dividers (PDs) covering a few megahertz to a few gigahertz. Conventional PDs designed using either distributed circuits or lumped elements cannot accomplish this purpose. In this paper, a novel ultrawideband wideband PD is developed with a combined design of both the distributed transmission line Wilkinson power divider (WPD) and the lumped compensation elements. The WPD is designed at 2.2GHz with a small configuration, while the loaded chip resistors and capacitors compensate its performance well at frequencies down to megahertz. The configuration and design method of the proposed divider is described, and a microstrip WPD is fabricated and measured. The simulated and measured responses of the WPD agree well over 10MHz∼4GHz, and both satisfy well the design specifications. To our knowledge, this is the first report of a WPD that covers an ultrawide frequency band from a few megahertz to a few gigahertz.
Through-silicon via (TSV) is proved to have great potential in high density, high performance integrated circuit. This work aims at reducing the loss of heterogeneous interconnection in three-dimensional integrated circuit (3D IC). The equivalent circuit models of TSV and redistribution layer (RDL) are established, they are in good agreement with finite element method (FEM) simulation results. An optimized structure with capacitive element is proposed to improve the transmission in heterogenous interconnection. The simulation indicates great transmission improvement at wide band from DC to 70GHz.
In this work, we evaluated a novel low loss and snapback-free silicon-on-insulator lateral insulated gate bipolar transistor (SOI LIGBT) by numerical simulation, which utilizes the inherent junction self-built potential (JSBP) to form depletion region at the anode. When the anode voltage (VAC) is less than built-in potential (Vbi), the introduced electron flowing channel between P-anode pillars is occupied by the depletion region, which hinders electron current from flowing into N-anode and limits the device to working in MOS mode. Furthermore, due to the offset effect for the JSBP by higher VAC, the depletion region disappears and the anode PN junction turns on, which makes the device work in IGBT mode forming normal electron and hole current. At the same forward voltage drop (VF) of 1.64V, extra electron flowing channel makes the turn-off loss (Eoff) of proposed JSBP LIGBT 22.1% lower than that of conventional (Conv.) LIGBT. Moreover, considering to the same Eoff of 0.3mJ/cm2, the depletion region with low VAC contributes to relatively enhanced conductivity modulation, which makes VF of proposed JSBP LIGBT reduce by 19.6% compared to separated shorted-anode (SSA) LIGBT, while also completely eliminates snapback effect. Therefore, the proposed JSBP LIGBT gains the best trade-off performance between VF and Eoff.
The novel shorted-anode silicon-on-insulator lateral insulated gate bipolar transistor (SOI LIGBT) with low loss and snapback-free is proposed and studied by numerical simulation, named the anode Schottky trench contact (ASTC) LIGBT in this paper. Due to the fixed anode resistance, the conventional shorted-anode LIGBT structure has the contradiction between the snapback-free and high forward voltage drop (VF). The novelty of proposed device is that, it makes full use of the lateral space charge region formed by the Schottky trench contact, so as to introduce the changed anode resistance by varying the anode voltage bias (VAC). The low VAC in the on-state achieves completely snapback-free with fully occupied channel by depletion region. The high VAC value in case of the turn-off process achieves fully opening of electron flowing channel with the disappearance of depletion region, which is conducive to the realization of barrier-free process for the electron extraction. Under the same VF of 1.42V at the anode current density JAC=100A/cm2, the turn-off time and turn-off loss (Eoff) of proposed ASTC LIGBT is reduced by 41.5% and 37.9%, respectively, compared with the conventional LIGBT. Therefore, it can be concluded that the proposed ASTC LIGBT achieves the best trade-off performance between VF and Eoff.
In this paper, a novel design method of wideband transmission line impedance transformers is proposed. All the circuit parameters are determined by a self-coded optimization program based on our derived formulas and an appropriately defined objection function. Three microstrip impedance transformers using different number and different mounting positions of the shunt short-circuited stubs are designed with a center frequency of 4.0 GHz and a Chebyshev equal-ripple fractional bandwidth of 80.0%. The measured results agree well with the predicted ones, showing that the proposed design method has adequate freedom in choosing both the number and the mounting positions of the short-circuited stubs, and novel wideband transmission line impedance transformers can be developed with many different configurations.
This paper presents a discrete-time (DT) 4th-order ΔΣ modulator using a 2nd-order noise-shaped integrating quantizer (NSIQ). By adding a passive finite impulse response (FIR) filter to the 1st-order NSIQ, the proposed quantizer has obtained 2nd-order noise shaping ability, without extra power consumption. By incorporating the digital integrator, the linearity requirement of the quantizer is relaxed. The proposed modulator is fabricated in a 0.18μm CMOS process, and operates at 1MS/s achieves a peak signal-to-noise-and-distortion ratio (SNDR) of 106.9dB in a 10kHz bandwidth while consuming 240μW with 1.8V power supply.