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This article proposes a packaged standalone $LC$ -voltage-controlled oscillator (VCO) based on self-biased (SB) switched capacitor array (SCA) to facilitate large frequency tuning-range (TR). The proposed SB SCA achieves better supply noise rejection and is robust to quad flat no-lead package (QFN) package parasitics when compared with other existing SCA topologies without compromising the quality factor ($Q$ -factor) of the SCA in OFF-state. A prototype SB SCA-based $LC$ -VCO designed and fabricated in United Microelectronics Corporation (UMC) 65-nm complementary metal oxide semiconductor (CMOS) process oscillates from 1.54 to 2.54 GHz having a TR of 40% achieving a phase noise (PN) of $\approx -96$ dBc/Hz at 100 kHz offset and an figure of merit (FoM) of ≈174 dBc/Hz at 100 kHz offset while consuming 10 mW of power from 2.5 V supply, thereby making it ideal for applications requiring QFN-packaged standalone VCOs. [ABSTRACT FROM AUTHOR]

Power module heat dissipation with spatial inhomogeneity and induced nonuniform temperature distribution presents a challenging concern for system reliability due to thermo-mechanical stresses. These reliability challenges are especially important for nonplanar designs using 3-D packaging principles. Here, we develop a heat spreader thermal switch capable of actively reducing temperature gradients between silicon carbide (SiC) devices in a three-level T-type power converter, which can change depending on electronic operating conditions. The heat spreader thermal switch consists of a stainless-steel (SS) heat spreader and a copper sliding switch embedded within the spreader. Heat transfer from the SiC devices and within the spreader can be controlled by moving the slider between positions within the spreader. To understand heat transfer mechanisms and design the heat spreader thermal switch, we conducted 3-D finite element method simulations to calculate the minimum attainable temperature difference between SiC devices. We used the finite element simulation to quantify the reduction in junction temperature swing during dynamic operation and coupled the results to the Coffin–Manson reliability model to quantify lifetime to failure. We integrated the heat spreader thermal switch with one phase of a three-phase T-type converter and demonstrated isothermalization at different working conditions. At 2.4-kW converter power, each hot SiC device dissipated 4.7 W of heat, resulting in a device case temperature of 43 °C, with each cold SiC device dissipating 1.7 W at 38 °C. The device-to-device temperature difference was decreased from 5 °C to 0 °C by moving the switch a distance of 20 mm. Finite volume method (FVM) simulations of the conjugate heat transfer problem validate the experimental results and support analysis of key performance parameters. This work demonstrates successful isothermalization of a power converter with an active heat spreader thermal switch and develops simulation and design guidelines for successful electro-thermal codesign and implementation of thermal switches for other electronics applications for which isothermalization and enhanced device reliability is a key issue. [ABSTRACT FROM AUTHOR]

A study into the manufacturing considerations for developing a frequency reconfigurable antenna solution using a low-cost inkjet printing technique is presented in this article. The solution uses an off-the-shelf printer, cartridges filled with nanoparticle silver ink, and inexpensive electronic components. In this study, two conductive patches are printed on an inexpensive polyethylene terephthalate (PET) substrate, which can provide both switching and tuning by repositioning and rearranging of the components in a single-layer design configuration. The conductive silver provides an insight into the quality of the printed area. Furthermore, it provides information on potential procedures to mount and reattach the components. Inexpensive capacitors and p-i-n diodes were affixed onto the printed aperture using conductive adhesive to create complimentary dipoles for frequency reconfiguration. A single-band switching solution switches between two adjacent frequency bands. A dual-band tuning solution demonstrates dynamic tuning between a range of frequencies. Simulated and measured results are in good agreement with one another. An assortment of bands of operations allows the antennas to be suitable for mobile communication, wireless local area network (WLAN), and sensing applications. The dual-band nature of the tunable antenna can act perfectly as a bridge among 3G, 4G, and 5G communication bands. [ABSTRACT FROM AUTHOR]

One of the most significant challenges for the fabrication of any microelectro-mechanical-system (MEMS) device is the low cost and high throughput packaging of the device to protect it from the environmental particles, moisture, and contaminations. In this work, an RF-MEMS switch for millimeter-wave (mm-wave) applications is monolithically integrated into the aluminum-based back-end-of-line (BEOL) of a 130-nm bipolar CMOS (BiCMOS) technology by wafer-level thin-film encapsulation (WLE). Both wet and vapor release techniques are developed and demonstrated for the release of the MEMS device, prior to wafer-level encapsulation packaging. The final device encapsulation is realized as wafer-level packaging with a 3- $\mu \text{m}$ thick metal grid using a stack of Ti/TiN/AlCu/Ti/TiN layers. Finally, a silicon dioxide deposition process with a high deposition rate (HDR) is applied for the full encapsulation of the release holes. The impact of the encapsulation on the RF-MEMS switch performance is evaluated by low-frequency $C$ – $V$ and high-frequency $S$ -parameter measurements at $D$ -Band. The results indicate the full function of the device without a significant performance drop. The encapsulation does not require an extra mask and it is developed as 8-in wafer-level process, thus providing a low cost and high throughput solution for RF-MEMS device encapsulation and packaging. [ABSTRACT FROM AUTHOR]

Integrated voltage regulator (IVR)-based power delivery architectures have become a growing trend in high-performance computing (HPC) systems. Integrated power delivery architectures typically feature high-frequency switching devices and embedded passive components, which can be integrated either inside the die or in the package. However, dense functional integration in such architectures though necessary brings a new set of challenges to system designers. In this article, we study the impact of heterogeneous integration on the design of power delivery architectures that addresses issues related to electrical, thermal, and electromagnetic domains through test cases. The key design problems arising out of heterogeneous integration and the solutions for each of the domains are identified. Although the electrical impedance profile seen by the load becomes flatter in the frequency domain with fewer resonances, noise coupling at the load increases due to the close proximity of noise sources. The electromagnetic interference (EMI) levels are higher, and therefore, more EMI and noise mitigating filters are needed for judicious placement at the package and die level. High thermal resistance associated with embedded passives results in a threshold for power losses in embedded inductors beyond which the conventional top-level cooling is insufficient and a local cooling solution is needed. [ABSTRACT FROM AUTHOR]

High-density package-embedded inductors enable the miniaturization of high conversion ratio integrated voltage regulators (IVRs). In this work, we present a new embedded inductor structure along with a new performance metric called effective ac resistance per unit inductance and how the inductor sets constraints to the power stage topology. The proposed performance metric depends on the converter duty cycle and frequency and uses the inductor current harmonics, its inductance and resistance spectra, and the large-signal response to compute the inductor losses. No information of the inductor volume or its magnetic field distribution is used. The proposed embedded inductor structure shows a toroidal field distribution using a combination of slots through a magnetic sheet and vias through these slots. The new structure enables the fabrication of several inductors in the same magnetic substrate for multiphase IVR. The proposed inductors are fabricated and the metric is demonstrated with measurements using a high saturation magnetic material, where an interesting relation between the small- and large-signal losses was observed. [ABSTRACT FROM AUTHOR]