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This article presents a design approach of a band-pass filter which is fabricated on an integrated passive device process and is capable of operating over the unlicensed 60-GHz band (57–64 GHz). The band-pass filter proposed in this article evolves from a typical one comprising two identical, mirrored open-loop half-wavelength microstrip line resonators. The experimental results demonstrate an insertion loss of less than 2.4 dB, a return loss of better than 10 dB over the 60-GHz band, and a 3-dB bandwidth of 24 GHz (∼42%). The simulation and measurement results are well matched up to 110 GHz. This filter is suited for system-in-a-package V-band front-end systems. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:199–202, 2016

Ruthroff-type transmission line transformers (TLTs) and baluns prevail over their broadband and low-loss performance. A typical Ruthroff-type balun with a 1:4 step-up impedance transformation ratio was successfully presented using integrated passive devices (IPDs) process. Moreover, two proposed baluns with step-down impedance transformation ratios of 1:1 and 9:4 were developed by modifying the combination of one Ruthroff-type TLT and one Ruthroff-type balun. The two proposed impedance step-down baluns whose balanced impedance is lower than unbalanced impedance make Ruthroff-type balun more flexible for applications; meanwhile, fabricating the baluns using IPD process can help to enhance the low-loss performance. The measured results show that the proposed 1:1 balun exhibits an insertion loss of 0.46 dB with 1-dB fractional bandwidth of 138.9%, and the proposed 9:4 balun exhibits an insertion loss of 0.75 dB with 1-dB fractional bandwidth of 72.4%. The chip areas of the proposed 1:1 and 9:4 baluns, including the pads, are 0.6 and 0.64 ${\rm mm}^{2}$ , respectively. The two proposed baluns are the first on-chip step-down Ruthroff-type baluns and having an option of center tap, which is highly contributive to wideband and high-efficiency power amplifier design.

This paper presents a broadband and high-efficiency integrated CMOS-integrated passive device (IPD) power amplifier (PA) with heterogeneous integration of active devices that are fabricated using 0.18 μm CMOS technology and passive components that are fabricated using IPD technology. The passive components that are fabricated using IPD technology have the advantages of high-Q, low-loss performance, and low cost. By replacing the conventional series resonant output matching network of class-E PA with a broadband Ruthroff-type transmission line transformer (TLT), the proposed PA exhibits broadband characteristics. It performs efficiently owing to the benefits of the low-loss TLT and the switching mode operation of the class-E PA. The measurements demonstrate an output power of more than 25.64 dBm and a power-added efficiency (PAE) of more than 40.2% over the bandwidth from 2 to 3 GHz. The peak output power and PAE are 26.18 dBm and 47.4%, respectively.

This article presents a 5-GHz band low phase noise CMOS voltage controlled oscillator (VCO) based on a high quality factor above-IC inductor that is stacked on the top of a 0.18-μm RF CMOS process using wafer level package technology. The measured phase noise of the VCO is −119.8 dBc/Hz at 1 MHz offset frequency, which is an improvement of 6 dB compared to a conventional VCO with on-chip CMOS inductor. The design challenge of the grounding of the above-IC inductor stacked on the CMOS structure is investigated in this work. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2051–2055, 2013

A compact 60-GHz band branch-line coupler using cpacitively loaded lower-ground coplanar-waveguide (LG-CPW) lines has been successfully demonstrated in a glass-substrate integrated passive device technology. The fabricated coupler has a size reduction of more than 83% compared to that of a conventional CPW branch-line coupler. The capacitive loading is achieved by utilizing the signal layer and the LG of the LG-CPW structure to form microstrip open-circuited stubs. The measured results show a phase error of less than 0.5° between the coupler's output ports and an amplitude imbalance of less than 1.2 dB over the frequency band 57-64 GHz. The measurements also show that both the return loss and isolation are better than 25 dB at 60 GHz and better than 15 dB over the 57-64-GHz band. The proposed coupler is well suited for low-cost high-performance system-on-package V-band radio front ends for high data rate applications.

This paper presents two voltage controlled oscillators (VCOs) operating at 5.42 and 5.76 GHz implemented in 0.18-μm complementary metal-oxide semiconductor (CMOS) technology with integrated passive device (IPD) inductors. One IPD inductor was stacked on the top of the active region of the 5.76-GHz VCO chip, whereas the other IPD inductor was placed on the top of the 5.42-GHz VCO CMOS chip but far from the its active region. The high-quality IPD inductors reduce the phase noise of the VCOs. The measurements of the two VCOs indicate the same phase noise of -120 dBc/Hz at 1 MHz offset frequency. These results demonstrate a 6-dB improvement compared to the VCO using an on-chip inductor. This paper also presents the effect of the coupling between the IPD inductor and the active region of the chip on the phase noise performance.

In electronic commerce web sites, recommender systems are popularly being employed to help customers in selecting suitable products to meet their personal needs. These systems learn about user preferences over time and automatically suggest products that fit the learned model of user preferences. Traditionally, recommendations are provided to customers depending on purchase probability and customers' preferences, without considering the profitability factor for sellers. This study attempts to integrate the profitability factor into the traditional recommender systems. Based on this consideration, we propose two profitability-based recommender systems called CPPRS (Convenience plus Profitability Perspective Recommender System) and HPRS (Hybrid Perspective Recommender System). Moreover, comparisons between our proposed systems (considering both purchase probability and profitability) and traditional systems (emphasizing an individual's preference) are made to clarify the advantages and disadvantages of these systems in terms of recommendation accuracy and/or profit from cross-selling. The experimental results show that the proposed HPRS can increase profit from cross-selling without losing recommendation accuracy.

Two broadband, low-loss Ruthroff-type transmission line transformers (TLTs) that are implemented in integrated passive devices (IPD) technology and intended for use in IEEE 802.11b/g WLAN systems are presented in this paper. The TLTs are realized by spiral broadside-coupled lines with proper characteristic impedances to optimize the insertion loss and bandwidth. The measured minimum insertion losses of 1∶4 and 1∶9 TLTs are 0.5 dB at 2.2 GHz and 0.57 dB at 2.4 GHz, respectively. The correspondent 1-dB bandwidths of these TLTs are 175% and 140%. The chip areas of the TLTs are 0.27 mm2 and 0.34 mm2.

This article presents and discusses the design of RF circuits using Integrated Passive Devices (IPDs) technology appropriate for the development of low-cost and high performance System-in-Package (SiP) wireless transceivers. Two examples, a 6-GHz voltage-controlled oscillator (VCO) and a 60-GHz 90° coupler are introduced to demonstrate the implementation of RF circuit design using an IPD process. Experimental results of the VCO and the 90° coupler will be presented and compared with the simulation results.

A reduced size rat-race coupler is proposed and designed for operation in the 60-GHz band (57–64 GHz) and is implemented in a glass-substrate IPD (Integrated Passive Devices) technology. A size reduction of 75% compared to that of a conventional rat-race coupler has been achieved by using high impedance lower-ground coplanar waveguide (LG-CPW) transmission lines that are loaded at their ends with microstrip open-circuited stubs. The experimental results of the coupler exhibited an amplitude imbalance of less than 0.5 dB and a phase variation of 5-degrees over the 57–64 GHz band. The achieved measured return loss is greater than 15 dB and the isolation is greater than 24 dB over the 57–64 GHz band. The measured results confirm the potential of the proposed rat- race coupler for use in low-cost, high performance radio front ends for 60-GHz band system-on-package radio-over-fiber communication systems.

A 90-nm CMOS single-stage low-noise amplifier with vertical planar waveguide (VPW) matching elements for use in millimeter-wave (mmW) transceivers has been developed and tested. The experimental results showed a noise figure of less than 4.1 dB and a gain higher than 10 dB in a frequency range of 57–58 GHz, and an input third-order intercept (IIP3) point greater than 3 dBm. The measured power consumption is 15.2 mW from a 1.5V supply. The proposed design is well suited for multi-gigabit mmW wireless systems.

A complete CMOS wideband low noise amplifier (LNA) has been designed with off-chip passive device. The input inductor with integrated passive device (IPD) is used for input matching and NF improvement due to its high quality factor (Q). The large inductance of 4.7 nH of choke is used for covering the bandwidth of 2∼11 GHz, which is stacked on the top of CMOS for chip-area saving. Besides, the interaction between CMOS and IPD for passive devices is also considered in the work. The CMOS wideband LNA is with the merits of cost-effective and high-performance compared to the pure CMOS circuit.

This paper presents the calibration procedure using a five-port calibration kit based on receiver mode in vector network analyzer (VNA). After de-embedding the phase/amplitude errors from cal-kit, the quadrature phase accuracy and amplitude error of a quadrature voltage controlled oscillator (QVCO) can be directly obtained using on-wafer testing with a single contact. A 5 GHz QVCO was tested to demonstrate the feasibility of measurement. The I/Q mismatch on both phase and amplitude of the QVCO were precisely measured. Only single probe contact is required during the measurement that minimizes the uncertainty.

In this paper, the log domain low-pass filter based on the MOSFET square law is proposed. This approach demonstrates that the cutoff frequency of the low-pass filter is not only attainable at megahertz frequencies but also tunable electronically. In addition, implemented by current-mode square-root circuit blocks, current mirrors and capacitors, the proposed low-pass filter can be operated with a 3.3 V power supply voltage. The proposed circuit has been simulated in 0.35 /spl mu/m CMOS technology, and the simulation results show that the proposed circuit has the merits of high frequency operation, tuneability, low power supply voltage operation.

A 15-60 GHz asymmetric broadside coupled balun fabricated in the standard TSMC 0.18 μm CMOS process is demonstrated. Using the broadside tight coupling technique, the balun is achieved with wide bandwidth and low insertion loss and utilises the inherent three-dimensional multilayer structure in CMOS technology. The balun achieves bandwidth of over 120%, the minimum insertion loss is better than 1.1 dB, amplitude difference is less than 1 dB and phase difference is less than 5deg (15-60 GHz). The occupied chip area is only 0.06 mm 2 .