In this paper, the research advances in silicon based millimeter wave and THz ICs in the State Key Laboratory of Millimeter Waves is reviewed, which consists of millimeter wave amplifiers, mixers, oscillators at Q, V and W and D band based on CMOS technology, and several research approaches of THz passive ICs including cavity and filter structures using SIW-like (Substrate Integrated Waveguide-like) guided wave structures based on CMOS and MEMs process. The design and performance of these components and devices are presented.

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A low cost, ultra small Radio Frequency (RF) transceiver module with integrated antenna is one of the key technologies for short range millimeter-wave wireless communication. This paper describes a 60GHz-band transmitter module with integrated dipole antenna. The module consists of three pieces of low-cost organic resin substrate. These substrates are vertically stacked by employing Cu ball bonding 3-dimensional (3-D) system-in-package (SiP) technology and the MMIC's are mounted on each organic substrates by using Au-stud bump bonding (SBB) technique. The planer dipole antenna is fabricated on the top of the stacked organic substrate to avoid the influence of the grounding metal on the base substrate. At 63GHz, maximum actual gain of 6.0dBi is obtained for fabricated planar dipole antenna. The measured radiation patterns are agreed with the electro-magnetic (EM) simulated result, therefore the other RF portion of the 3-D front-end module, such as flip chip mounted IC's on the top surface of the module, does not affect the antenna characteristics. The results show the feasibility of millimeter-wave low cost, ultra small antenna integrated module using stacked organic substrates.

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This paper describes latest RF Automated Test Equipment (RF ATE) technologies that include device under test (DUT) connections, a calibration method, and an RF test module mainly focusing on low cost of test (COT). Most important respect for low COT is how achieve a number of simultaneous measurements and short test time as well as a plain calibration. We realized these respects by a newly proposed calibration method and a drastically downsized RF test module with multiple resources and high throughput. The calibration method is very convenient for RF ATE. Major contribution for downsizing of the RF test module is RF circuit technology in form of RF functional system in package (RF-SIPs), resulting in very attractive test solutions.

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The design and measured results of a 120-GHz transmitter and receiver chipset are described in this paper. A simple on-off keying (OOK) modulation is adopted for low power consumption. The proposed transmitter and receiver are fabricated using 65-nm CMOS technology. The current consumption of the transmitter and receiver are 19.2mA and 48.2mA respectively. A 9-Gbps PRBS is successfully transferred from the transmitter to the receiver with the bit error rate less than 10^-9.

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Recently, dynamic power supply voltage techniques, such as an Envelope Elimination and Restoration power amplifier (EER-PA) or Envelope-Tracking Power amplifier (ET-PA), have been attracting much attention because they can maintain high efficiency in large back-off region [1]-[6]. The dynamic power supply voltage techniques cause strong nonlinearity compared to a conventional power amplifier, hence a memoryless Digital Predistortion (DPD) technique is indispensable for these efficiency enhancement techniques. However, the performance of the memoryless DPD is degraded due to the frequency response of the envelope amplifier in the dynamic power supply voltage techniques [7]-[9]. In this paper, we clarify the degradation mechanisms of the memoryless DPD for the EER-PA due to the frequency response of the envelope amplifier based on the results of two-tone tests, and propose an analytical model for improving the performance of the memoryless DPD developed for the EER-PA. In addition, a prototype EER-PA is developed and we demonstrate that the residual distortion of the developed EER-PA with conventional memoryless DPD algorithm is compensated by the new algorithm based on the proposed analytical model. In the two-tone test, third-order intermodulation distortion (IMD3) with a tone spacing from 100kHz to 4MHz is improvement by up to 25dB by the memoryless DPD algorithm based on the proposed model. Measured adjacent channel leakage power ratio (ACPR) of the developed EER-PA is improved from -22.5dBc to -42.5dBc in the OFDM signal test with 1.08MHz bandwidth.

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This paper presents a novel design scheme for a band-switchable multi-band power amplifier (BS-MPA). A key point of the design scheme is configuring multi-section reconfigurable matching networks (MR-MNs) optimally in terms of low loss matching in multiple frequency bands from 0.7 to 2.5GHz. The MR-MN consists of several matching sections, each of which has a matching block connected to a transmission line via a switch. Power dissipation at an actual on-state switch results in the insertion loss of the MR-MN and depends on how the impedance is transformed by the MR-MN. The proposed design scheme appropriately transforms the impedance of a high power transistor to configure a low loss MR-MN. Numerical analyses show quantitative improvement in the loss using the proposed scheme. A 9-band 3-stage BS-MPA is newly designed following the proposed scheme and fabricated on a multi-layer low temperature co-fired ceramic substrate for compactness. The BS-MPA achieves a gain of over 30dB, an output power of greater than 33dBm and a power added efficiency of over 40% at the supply voltage of 4V in each operating band.

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This paper presents the design and implementation of 0.9-4.8GHz CMOS power amplifier (PA) with improved group delay variation and gain flatness at the same time for UWB transmitters. This PA design employs a two-stage cascade common source topology, a resistive shunt feedback technique and inductive peaking to achieve high gain flatness, and good input matching. Based on theoretical analysis, the main design factor for group delay variation is identified. The measurement results indicate that the proposed PA design has an average gain of 10.2 ± 0.8dB while maintaining a 3-dB bandwidth of 0.57 to 5.8GHz, an input return loss |S₁₁| less than -4.4dB, and an output return loss |S₂₂| less than -9.2dB over the frequency range of interest. The input 1dB compression point at 2GHz was -9dBm while consumes 30mW power from 1.5V supply voltage. Moreover, excellent phase linearity (i.e., group delay variation) of ±125ps was achieved across the whole band.

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This paper shows a new pulse swallow programmable frequency divider with the division step size of 0.5. To realize the division step size of 0.5 by a conventional pulse swallow method, we propose a parallel dual modulus prescaler with the division ratio of P and P+0.5. It consists of simple circuit elements and has an advantage over the conventional dual modulus prescaler with the division step size of 0.5 in high frequency operation. The proposed parallel dual modulus prescaler with the division ratio 8 and 8.5 is implemented in the 0.13-µm CMOS technology. The proposed architecture achieves 7 times higher frequency operation than the conventional one theoretically. It is verified the functions over 5GHz.

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In this paper, a dual-band bandpass filter (BPF) of multilayer suspended stripline (SSL) structure and an SSL diplexer composed of a low-pass filter (LPF) and a high-pass filter (HPF) are proposed. Bandstop structure creating transmission zeros is adopted in the BPF and diplexer, enhancing the signal selectivity of the former and increasing the isolation between the diverting ports of the latter. The dual-band BPF possesses two distinct bandpass structures and a bandstop circuit, all laid on different metallic layers. The metallic layers together with the supporting substrates are vertically stacked up to save the circuit dimension. The LPF and HPF used in the diplexer structure are designed by a quasi-lumped approach, which the LC lumped-elements circuit models are developed to analyze filters' characteristics and to emulate their frequency responses. Half-wavelength resonating slots are employed in the diplexer's structure to increase the isolation between its two signal diverting ports. Experiments are conducted to verify the multilayer dual-band BPF and the diplexer design. Agreements are observed between the simulation and the measurement.

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This paper proposes a new three-mode resonator, which consists of a parallel-coupled microstrip line resonator embedded with a slotline resonator, and develops a compact low-loss bandpass filter (BPF) with a sharp roll-off response because of four transmission zeros (TZ) located very near the passband. Resonance mechanism and properties of the three modes are first analyzed by using an eigen-mode analysis, and then an equivalent circuit model is established for expressing a novel coupling scheme of the developed BPF. It is made clear from the results of circuit analysis that the four TZs are produced because of multiple paths between the input/output stub lines formed by the three resonant modes and the direct source/load coupling. The validity of the proposed resonator and filter is supported by the comparison between simulated and measured results.

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In this paper, a new swept-frequency method for the measurement of the complex permittivity and permeability of materials is proposed. The method is based on the S-parameters measurement of a cylindrical material placed inside a rectangular waveguide, where the axis of the cylinder is perpendicular to the narrow waveguide walls. The usage of cylinders in measurement is beneficial because they are easy to fabricate and handle. A novel exact solution of the field scattered by the cylinder is developed. The solution is based on expanding the field in a sum of orthogonal modes in cylindrical coordinates. Excitation coefficients relating the cylindrical scattered field to the waveguide modes are derived, and are used to rigorously formulates the S-parameters. Measurement are performed in the S-band with two dielectric materials (PTFE, nylon), and in the X-band with one magnetic material (ferrite epoxy). The measurement results agree with those from the literature.

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In this paper, a simple and efficient design scheme for digital compensation of path imbalances in linear amplification with nonlinear component (LINC) transmitters is proposed to reduce signal distortion. For the LINC transmitters including path imbalances, an error vector magnitude (EVM) is analyzed and an optimal complex gain that minimizes the EVM is extracted. In addition, a straight-forward compensation scheme for the path imbalances is proposed using a least square method for complex gains of each radio frequency path. The effectiveness of the proposed method is compared with the other digital compensation methods. A LINC transmitter with multi-level quadrature amplitude modulation input signals is experimented to verify the performance of the suggested scheme. The proposed compensator can reduce the EVM and the adjacent channel power ratio of the output signals less than 2% and 45dBc, respectively.

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Recent years, millimeter wave applications for wireless communication have attracted much attention and expected. We focused on an NRD guide and sapphire which have the excellent low loss characteristics in millimeter wave region. In this paper, an NRD guide excited sapphire disk resonator and millimeter wave bandpass filter with narrow bandwidth using proposed resonators were designed and fabricated. As a result, it was realized that the 3-pole bandpass filter with center frequency 58.64GHz and 3dB bandwidth 273MHz. Moreover, its insertion loss was found to be about 1.5dB.

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A highly stable microwave exciter system has been developed for ⁸⁷Sr⁺ ion microwave frequency standards. The controller was built to optimize the transfer function of the phase-locked loop. The upper limit of the frequency tracking error achieved was 7.7×10^-15 at τ=1s. A phase frequency discriminator using an FPGA was also made and applied to a phase-locked loop. This paper reports on the design of and results obtained from the microwave exciter for Sr⁺ ion microwave frequency standards.

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We present the theory and experiment of metal-cavity nanolasers and nanoLEDs flip-chip bonded to silicon under electrical injection at room temperature. We first review the recent progress on micro- and nanolasers. We then present the design rule and our theoretical model. We show the experimental results of our metal-cavity surface-emitting microlasers and compare with our theoretical results showing an excellent agreement. We found the important contributions of the nonradiative recombination currents including Auger recombination, surface recombination, and leakage currents. Finally, experimental demonstration of electrical injection nanoLEDs toward subwavelength nanoscale lasers is reported.

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To meet the demand for light sources for on-chip optical interconnections, we demonstrate the continuous-wave (CW) operation of photonic-crystal (PhC) nanocavity lasers at up to 89.8°C by using InP buried heterostructures (BH). The wavelength of a PhC laser can be precisely designed over a wide range exceeding 100nm by controlling the lattice constant of the PhC. The dynamic responses of the PhC laser are also demonstrated with a 3-dB bandwidth of over 7.0GHz at 66.2°C. These results reveal the laser's availability for application to wavelength division multiplexed (WDM) optical interconnection on CMOS chips. We discuss the total bandwidths of future on-chip optical interconnections, and report the capabilities of PhC lasers.

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We propose and demonstrate a simple and novel technique to accelerate the carrier injection/depletion processes in an RSOA by applying instantaneous injection/depletion currents at the transition edges of the modulation signal to force the carrier density to respond at a high speed and, as a result, to increase its modulation speed. We theoretically and experimentally show that, by using the proposed technique, it is possible to obtain 5Gbit/s optical BPSK signal from an RSOA having a modulation bandwidth of only 0.9GHz.

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Wavelength demultiplexed light switching is numerically calculated in the variable index arrayed waveguide. Wavelength demultiplexed light is switched in 4 output ports by changing the refractive index of variable index arrayed waveguide with 16 array waveguides. In the calculation, the phase differences in each arrayed waveguide, and the diffraction in the star coupler are considered. In 4 output ports switching, numerically calculated the refractive index changes of 16 array waveguides are numerically calculated to obtain the 24 switching pattern, and also calculated the crosstalk of each switching.

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We have demonstrated switching characteristics in a wavelength switch based on multiple GaInAs/InP quantum wells. It consisted of straight arrayed waveguides with a linearly varying refractive index distribution. The refractive index can be changed via the thermo-optic (TO) effect. Using a Ti/Au thin-film heater to generate the TO effect, we realized four-port switching at four demultiplexed wavelengths. In addition, by changing the structure of the heater from rectangular to triangular, the power consumption for four-port switching was reduced by half.

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A dual-core spot size converter (DC-SSC) is integrated with a lateral grating assisted lateral co-directional coupler (LGLC) tunable laser by using no additional complicated fabrication processes. The excess loss due to the DC-SSC is only 0.5dB, and narrow full width half maximums (FWHMs) of vertical and horizontal far-field patterns (FFPs) produced by the laser are about 25° and 20°. This integration causes no degradations of the performance of the LGLC laser; in other words, it maintains good lasing characteristics, namely, wide tuning range of over 68nm and SMSR of over 35dB in the C-band under a 50°C semi-cooled condition.

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In order to realize millimeter-wave (MMW) 3-D system-in-package (SiP) front-end modules, we propose a 60-GHz band copper ball vertical interconnection structure, which interconnects between vertically stacked substrates. The structure enables ICs to be placed between the vertically stacked substrates. Since the diameter of the copper balls must exceed the thickness of the ICs, the distance between the substrates in the modules is larger than that of the flip-chip interconnection widely used in the MMW-band. Therefore, the conventional flip-chip interconnection does not scale for the interconnection between the substrates in MMW 3-D SiP front-end modules. The layout of grounded copper balls and the patterns of inner ground layers in the upper/lower substrates are designed using 3-D electromagnetic field simulation. The designed structure allows less than 1dB transmission loss up to 71.1GHz, compared with a through transmission line. The result is verified with fabrication and measurement and confirms the feasibility of MMW 3-D SiP front-end modules.

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This paper investigates a clock frequency generator for ultra-low-voltage sub-picosecond-jitter clock generation in future 0.5-V LSI and power aware LSI. To address the potential possible solution for ultra-low-voltage applications, a 0.5V clock frequency generator is proposed and implemented. Significant performances, in terms of sub 1-ps jitter, 50MHz-to-6.4GHz frequency tuning range with 2 bands and sub 1-mW P_DC, demonstrated the viable replacement of ring oscillators in low-voltage and low-jitter clock generator.

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The authors propose a new method of controlling the isolation of an RF splitter. In the proposed method, a bias current is superimposed on an RF signal to change the permeability of the ferrite core used in the splitter's transformer. By doing this, the splitter isolation can be controlled. Experimental results have shown that superimposing a bias current of 500mA improves device isolation by about 5dB without affecting the loss characteristics.

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A novel fabrication approach for electrochemical sensing of nicotinamide adenine dinucleotide (NADH) using neutral red (NR) functinalized carbon nanotube/plasma-polymerized film composite electrode is reported. The configuration of sensing electrode was NR-functionalized CNTs sandwiched between two acetonitrile PPFs on sputtered gold thin film. The NR as an electron transfer mediator shuttles the electron from the CNT to gold electrode. Due to the synergistic effect between NR and CNT, the resulting electrode showed the lower detection potential and the larger sensitivity (current) than that of NR or CNT alone. The sensor revealed a sensitivity of 29µA mM^-1cm^-2 at +0.15V vs. Ag/AgCl, linear dynamic range of 0.08-4.2mM, a detection limit of 18µM at S/N=3, and a response time of 7s.

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Polycrystalline Cu(In,Ga)Se₂ (CIGS) films were prepared by heat treatment of metallic precursors using dimethylselenium (Se(CH₃)₂), which is a less hazardous Se source than H₂Se gas. CIGS films were fabricated at various Se(CH₃)₂ supply rates. We investigated the effect of the Se(CH₃)₂ supply rate on the crystal phase and surface morphology of the films.

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