This paper proposes a novel waveguide intersection separating two H-plane waveguide systems from each other. If a four-port network in a four-fold rotational symmetry is completely matched, it has necessarily intersection properties. The proposed waveguide intersection consists of a square H-plane waveguide planar circuit connected four input/output waveguide ports in a four-fold rotational symmetry, and several metallic posts inserted at the junction without destroying the symmetry to realize a perfect matching. By optimizing the circuit parameters, high isolation properties are obtained in a relatively wide frequency band of about 8.6% for return loss and isolation better than 20 and 30 dB, respectively, for a circuit designed at 10 GHz. The proposed waveguide intersection can be analyzed by H-plane planar circuit approach, and possess advantages of compactness, simplicity, and high-power handling capability. Furthermore, an SIW intersection is designed by applying H-plane planar circuit approach to a waveguide circuit filled with dielectric material, and high isolation properties similar to H-plane waveguide intersection can be realized. The validity of these design concepts is confirmed by em-simulations and experiments.

Microwave/millimeter-wave phase and amplitude characteristics of the optically controlled phased array antenna with a different SMF for each antenna feed were measured. Suitable phases for the beam steering can be realized by the adjustment of the LD wavelength independently with multiple SMFs. In addition to the phase, amplitude of each antenna feed can be controlled stably using LD current without phase variation. Furthermore, effectiveness of the calibration method of the phased array using multiple SMFs by LD wavelength adjustment is experimentally verified. Excellent microwave/millimeter-wave phase characteristics using 2- and 3-element optically controlled phased array feed were experimentally demonstrated with calibration of the phases. Phase characteristics of the array using multiple SMFs were also compared with that using a single SMF experimentally.

This paper proposes an adaptive antenna using a combination of on-off and CMA algorithms. With the proposed technique, the on-off algorithm is first employed to search for a desired signal direction in which maximum received power is achieved. Then, interference is suppressed by performing CMA. Simulations are conducted according to the potential application of the proposed adaptive antenna. The simulation results show the SINR improvement implying that the proposed adaptive antenna can be applied to microwave RFID systems in order to resolve reader collision. Furthermore, the proposed adaptive antenna is implemented and then experimented. The experimental results verify that the proposed adaptive antenna can reduce interference resulting in the collision problem.

High-power protection switch utilizing a new stub/line selectable configuration is presented. By employing the proposed circuit topology, the insertion loss at receiving mode and the power handling capability at transmitting mode can be independently designed. Therefore, the proposed circuit is able to achieve low insertion loss at receiving mode while keeping high-power performance at transmitting mode. To verify this methodology, MMIC switch has been fabricated in Ka-band. The circuit has achieved the insertion loss of 2 dB, the isolation of 25 dB, and the power handling capability of 40 dBm at 5% bandwidth.

In this paper, we present a 0.18-µm CMOS fully integrated X-band shock wave generator (SWG) with an on-chip dipole antenna and a digitally programmable delay circuit (DPDC) for pulse beam-formability in short-range and hand-held microwave active imaging applications. This chip includes a SWG, a 5-bit DPDC and an on-chip wide-band meandering dipole antenna. By using an integrated transformer, output pulse of the SWG is sent to the on-chip meandering dipole antenna. The SWG operates based on damping conditions to produce a 0.4-V peak-to-peak (p-p) pulse amplitude at the antenna input terminals in HSPICE simulation. The DPDC is designed to adjust delays of shock-wave outputs for the purpose of steering beams in antenna array systems. The wide-band dipole antenna element designed in the meandering shape is located in the top metal of a 5-metal-layer 0.18-µm CMOS chip. By simulating in Momentum of ADS 2009, the minimum value of antenna's return loss, S 11, and antenna's bandwidth (BW) are -19.37 dB and 25.3 GHz, respectively. The measured return loss of a stand-alone integrated meandering dipole is from -26 dB to -10 dB with frequency range of 7.5-12 GHz. In measurements of the SWG with the integrated antenna, by using a 20-dB standard gain horn antenna placed at a 38-mm distance from the chip's surface, a 1.1-mVp-p shock wave with a 9-11-GHz frequency response is received. A measured 3-ps pulse delay resolution is also obtained. These results prove that our proposed circuit is suitable for the purpose of fully integrated pulse beam-forming system.

This paper presents Q factor analysis for FET oscillators employing distributed-constant elements. We replace the inductor of a lumped constant Colpitts circuit by a shorted microstrip transmission line for high frequency applications. Involving the FET's transconductance and the transmission line's loss due to both conducting metal and dielectric substrate, we deduce the Q factor formula for the entire circuit in the steady oscillation state. We compared the computed results from the oscillator employing an uniform shorted microstrip line with that of the original LC oscillator. For obtaining even higher Q factor, we modify the shape of transmission line into nonuniform, i.e., step-, tapered-, and partially-tapered stubs. Non-uniformity causes some complexity in the impedance analysis. We exploit a piecewise uniform approximation for tapered part of the microstrip stub, and then involve the asymptotic expressions obtained from both stub's impedance and its frequency derivatives into the active Q factor formula. Applying these formulations, we calculate out the value of capacitance for tuning, the necessary FET's transconductance and achievable active Q factor, and then finally explore oscillator performances with a microstrip stub in different shapes and sizes.

This paper presents a novel automated microwave filter tuning method based on successive optimization of phase and amplitude characteristics. We develop an optimization procedure to determine how much the adjusting screws of a filter should be rotated. The proposed filter tuning method consists of two stages; coarse and fine tuning stages. In the first stage, called coarse tuning, the phase response error of the target filter is minimized so that the filter roughly approximates almost ideal bandpass characteristics. Then in the second stage, called fine tuning, two different amplitude response errors are minimized in turn and then the resulting filter well approximate the ideal characteristics. Performance of the proposed tuning procedure is evaluated through some experiments of actual filter tuning.

We edit in this paper several archives on the research and development in the field of microwave circuit technology in Japan, that originated with the invention of Yagi-Uda antenna in 1925, together with generally unknown historical topics in the period from the 1920s up until the end of World War II. As the main subject, we investigate the origin and evolution of the Multiply Split-Anode Magnetron, and clarify that the basic magnetron technology had been established until 1939 under the direction of Yoji Ito in cooperation of expert engineers between the Naval Technical Institute (NTI) and the Nihon Musen Co., while the Cavity Magnetron was invented by Shigeru Nakajima of the Nihon Musen Co. in May 1939, and further that physical theory of the Multiply Split-Anode Cavity Magnetron Oscillation and the design theory of the Cavity Magnetron were established in collaboration between the world-known physicists and the expert engineers at the NTI Shimada Laboratory in the wartime. In addition, we clarify that Sin-itiro Tomonaga presented the Scattering Matrix representation of Microwave Circuits, and others. The development mentioned above was carried out, in strict secrecy, in an unusual wartime situation up until 1945.

This paper represents a low noise second harmonic oscillator using mutually synchronized Gunn diodes. A multi-layer MIC technology is adopted to reduce the circuit size of the oscillator. The oscillator consists of Gunn diodes, slot line resonators and strip lines. By embedding Gunn diodes in the slot line resonators, a harmonic RF signal can be generated very easily. The strip lines are used for the power combining output circuit. The shape of slot line resonator is square in order to achieve the low phase noise and the suppression of undesired harmonics. The second harmonic oscillator is designed and fabricated in K band. The output power is +8.89 dBm at the design frequency of 18.75 GHz (2f0) with the phase noise of -116.2 dBc/Hz at the offset frequency of 1 MHz. Excellent suppression of the undesired fundamental frequency signal (f0) of -33 dBc is achieved. Also, the circuit size is reduced by three-tenths relative to that of the previously proposed circuit.

An analog pre-distortion linearizer employing a radio frequency (RF) transistor with a self base bias control circuit is proposed. The self base bias control circuit extracts the envelope from the modulated input RF signal of the RF transistor and automatically controls its base current according to the extracted envelope. As a result, the proposed linearizer realizes positive gain deviation at high input power level. By adding a resistor between the RF transistor and the self base bias control circuit, the negative gain deviation can be derived. The design of the proposed lineaizer is described with taking the envelope frequency response of the self base bias control circuit into consideration. The fabricated linearizer achieves the adjacent channel power leakage ratio (ACLR) improvement of 8.1 dB for a 2 GHz-band, 10 W-class GaAs FET high-power amplifier (HPA) with negative gain deviation for W-CDMA base stations. It also achieves the ACLR improvement of 8.3 dB for a LDMOS HPA with positive gain deviation for the same application.

A direct-conversion receiver integrated with the CMOS subharmonic frequency tripler (SFT) for V-band applications is designed, fabricated and measured using 0.13-µm CMOS technology. The receiver consists of a low-noise amplifier, a down-conversion mixer, an output buffer, and an SFT. A fully differential SFT is introduced to relax the requirements on the design of the frequency synthesizer. Thus, the operational frequency of the frequency synthesizer in the proposed receiver is only 20 GHz. The fabricated receiver has a maximum conversion gain of 19.4 dB, a minimum single-side band noise figure of 10.2 dB, the input-referred 1-dB compression point of -20 dBm and the input third order inter-modulation intercept point of -8.3 dB. It draws only 15.8 mA from a 1.2-V power supply with a total chip area of 0.794 mm0.794 mm. As a result, it is feasible to apply the proposed receiver in low-power wireless transceiver in the V-band applications.

We have been studying a superconducting quantum-computing system where superconducting qubits are controlled and read out by rapid single-flux- quantum (RSFQ) circuits. In this study, we designed and fabricated an RSFQ microwave chopper, which turns on and off an externally applied microwave to control qubit states with the time resolution of sub-nanosecond. The chopper is implemented in a microwave module and mounted in a dilution refrigerator. We tested the microwave chopper at 4.2 K. The amplitude of the output microwave was approximately 100 µV which is much larger than that of previously designed chopper. We also confirmed that the irradiation time can be controlled by RSFQ control circuits.

A design of the tunable superconducting power filter is described. The filter consists of superconducting microwave cavities with a mechanical tuning method. The electromagnetic simulations using niobium cavity suggested that there were conditions where the resonator with high-unloaded Q can realize a fractional center frequency change of more than 10% by using a Nb rod moving in the cavity. The simulations approximated the resonant frequency dependence of the rod moved by a cryogenic actuator in the tunable cavity experiment. In addition, the simulation of the power handling capability showed a feasibility of the value more than 50 dBW.

A 0.4-5.8 GHz SiGe-MMIC quadrature modulator (Q-MOD) employing a self current controlled mixer for cognitive radio is described. The self current controlled mixer consists of a Gilbert cell mixer and a self current control circuit which is composed of both a current feedback circuit and an output buffer amplifier. The self current control circuit automatically controls the mixer current according to the output power level, and improves the linearity over wide radio frequency (RF) range. Simulation results show that the proposed Q-MOD realizes 1 dB compression point (P1 dB) improvement of more than 3.0 dB compared to the conventional Q-MOD at the frequencies of 0.4, 0.8, 1.95, 5.2 and 5.8 GHz. The fabricated Q-MOD achieves P1 dB improvement of more than 2.8 dB under the same condition. It also improves the output power with error vector magnitude (EVM) of 3.0% (Pout@EVM=3.0%), and achieves the Pout improvement of more than 2.7 dB under the modulation conditions of UHF wireless system (OFDM/16QAM, 0.4 GHz), W-CDMA (HPSK/QPSK, 0.8 GHz/1.95 GHz) and wireless-LAN (OFDM/64QAM, 5.2 GHz/5.8 GHz).

This letter presents the construction and design equations of a lumped element Wilkinson divider with dual-band operation. This divider is constructed of series and parallel LC resonant circuits, and an isolation resistor. The element values can be uniquely determined by giving the two frequencies for operation as a Wilkinson divider and the load resistance. An 800 MHz/2 GHz dual-band Wilkinson divider is treated as a design example, and its operation is verified by simulation and experiment. The fabricated divider has compact dimensions of 3.564 mm2.

A flexible noise de-embedding method for on-wafer microwave measurements of silicon MOSFETs is presented in this study. We use the open, short, and thru dummy structures to subtract the parasitic effects from the probe pads and interconnects of a fixtured MOS transistor. The thru standard are used to extract the interconnect parameters for subtracting the interconnect parasitics in gate, drain, and source terminals of the MOSFET. The parasitics of the dangling leg in the source terminal are also modeled and taken into account in the noise de-embedding procedure. The MOS transistors and de-embedding dummy structures were fabricated in a standard CMOS process and characterized up to 20 GHz. Compared with the conventional de-embedding methods, the proposed technique is accurate and area-efficient.

In this paper, the research advances in SIW-like (Substrate Integrated Waveguide-like) guided wave structures and their applications in the State Key Laboratory of Millimeter Waves of China is reviewed. Our work is concerned with the investigations on the propagation characteristics of SIW, half-mode SIW (HMSIW) and the folded HMSIW (FHMSIW) as well as their applications in microwave and millimeter wave filters, diplexers, directional couplers, power dividers, antennas, power combiners, phase shifters and mixers etc. Selected results are presented to show the interesting features and advantages of those new techniques.

An L-band 4-bit RL/RC-switched active phase shifter using differential switches is developed. It employs RL/RC circuits in the design of series feedback loops of the quadrature differential amplifier and achieves 90, 45, and 22.5of phase shift by switching on and off the RL/RC circuits alternatively. On the other hand, a 180phase shift is achieved with the use of a phase difference between the differential outputs. By cascading all four bits, an insertion gain of 16 to 23 dB, a phase error of less than 8.5, and an RMS phase error of 4.6have been achieved at 1 GHz.

The superconducting band-pass filter has small insertion loss and excellent out-of-band rejection properties. It has been put to practical use in a number of applications. However, in order to expand its range of application, a tuning technique that can restore the filter characteristics is needed. We propose an automatic tuning system using a trimming library and checked the feasibility of the system by tuning a forward-coupled filter with three resonators. The results show that the trimming library method is an effective way of automatically improving the filter characteristics.

This paper describes a novel Wilkinson power divider operating at two arbitrary different frequencies. The proposed divider consists of two-section transmission lines and a series RLC circuit connected between two output ports. The circuit parameters for a dual-band operation are derived by the even/odd mode analysis. Equal power split, complete matching, and good isolation between two output ports are numerically demonstrated. Dual-band and broadband Wilkinson power dividers can be successfully designed. Finally, verification of this design method is also shown by electromagnetic simulations and experiments.