Search

Novel design approaches for ultra-high-order subharmonic self-oscillating mixers (SOMs) based on a multiple-element technique are presented. They are of high impact for high-end millimetre-wave systems as subharmonic operation reduces local oscillator frequency requirements. An outline of the basic theory and a design procedure for arbitrary high mixing orders are presented, and a sixth-order SOM is fabricated for the first time. The prototype exhibits a conversion gain of +2.8 dB at an RF input frequency of 7.4 GHz. [ABSTRACT FROM AUTHOR]

The coplanar stripline (CPS) suffers from excessively high characteristic impedance which makes the design of filters difficult. Proposed is a slow-wave rail CPS (R-CPS) transmission line for the design of a stepped impedance lowpass filter. The R-CPS exhibits an extended low-impedance limit not achievable by conventional CPS, while retaining the advantages of the CPS. It also improves the performance of the filter in terms of suppression of the spurious harmonic passbands and reduces the filter size. [ABSTRACT FROM AUTHOR]

A compact filter for ultra-wideband (UWB) applications is proposed and developed through quasi-equal allocation of the first three resonant frequencies of a stub-loaded resonator together with strong input/output excitation. Measured results show low insertion loss and flat group delay in the entire passband as well as a wide stopband. The size for this single-layer UWB filter without feeding lines is only 9.5×5 mm (0.53 λg ×0.28 λg in which λg is the guided wavelength of 50 Ω microstrip at the centre frequency). [ABSTRACT FROM AUTHOR]

A self-equalised pseudo-elliptical filter on the basis of substrate integrated waveguide technology is proposed and demonstrated over the Ka-band range. The extracted-pole technique is used to synthesise a sixth-order filter with non-resonating nodes. Measured results of the filter exhibit a high selectivity and a minimum in-band insertion loss of about 2.0 dB and small inband group delay variation. [ABSTRACT FROM AUTHOR]

A compact multilayer ultra-wideband (UWB) six-port device, composed of power combiners and dividers, is presented. Implemented in hybrid microstip/stripline technology, the six-port can be used as a front-end transceiver. The operational frequency spans a range of 3–5 GHz (50% fractional bandwidth), suitable for pulse signals in UWB single channel communication. Measurements and simulation results validate circuit performance as a transceiver using quaternary phase spectrum modulation. [ABSTRACT FROM AUTHOR]

A BST ferroelectric thin-film microwave phase shifter with interdigital capacitors on TiO2/Si substrate is presented. The interdigital capacitors have 230 µm signal width, 100 µm signal to ground gap, and 10 µm finger gap. The device, with phase shifts of 142° and FoM of 107.3°/dB applied voltage of 50 V at 16 GHz, has been realised. The TiO2 buffer layer grown by ALD enables successful integration of BST-based microwave tunable devices with Si wafer. [ABSTRACT FROM AUTHOR]

The details of a monolithically integrated, five-channel, dual carrier/wavelength per channel, polarisation multiplexed, coherent QPSK receiver on InP operating at 114 Gbit/s per channel are discussed. [ABSTRACT FROM AUTHOR]

A novel super-broadband planar monopulse comparator is presented, and demonstrated experimentally. This comparator is based on a recently discovered 180° hybrid coupler derived from the conventional Wilkinson divider. Because of its symmetric configuration, the proposed comparator exhibits frequency-independent nulls at its three difference output ports and therefore features a quasi unlimited bandwidth. This property substantially enhances the overall broadband resolution performance of monopulse comparators with direct benefits in tracking radar applications. [ABSTRACT FROM AUTHOR]

Proposed is a new substrate-integrated waveguide to air-filled rectangular waveguide (WR-10) transition for use at millimetre-wave frequencies. The transition combines the features of low return loss and low insertion loss over the 42 GHz bandwidth and it can be manufactured without a high degree of complexity. A 75-115 GHz band prototype of the proposed broadband transition is designed and fabricated. Simulated and measured results of the prototyped back-to-back transition show good agreement. [ABSTRACT FROM AUTHOR]

A novel reader loop-type antenna for ultra-high-frequency (UHF) near-field radio frequency identification (RFID) applications is presented. This antenna, printed on a 0.8 mm-thick FR4 substrate with a diameter of 16 cm, is composed of four curved strips and four pairs of coupled stubs, and achieves a wide impedance bandwidth from 840 to 1300 MHz. The proposed structure can make large currents along the loop so that a strong and uniform magnetic field distribution is excited in the region around the antenna. Measurements show that the antenna operating with a commercial reader demonstrates good performance of tag identification with inductive coupling for near-field RFID applications. [ABSTRACT FROM AUTHOR]

The hybrid integration of a dielectric antenna together with an MMIC low-noise amplifier in a 60 GHz front-end is presented. It is demonstrated how a low-loss substrate integrated dielectric antenna can efficiently be interconnected at miniature scale with the coplanar waveguide input of the MMIC. The experimentally obtained return loss is better than 11 dB from 55 to 65 GHz. Transmission path loss measurements of a wireless link confirm the low-loss potential of this approach for millimetre-wave front-ends. [ABSTRACT FROM AUTHOR]

Hot-carrier-induced degradation in an n-type lateral diffused metal-oxide-semiconductor (LDMOS) transistor is investigated. Based on experimental data and technology computer-aided-design simulations, hot-electron injection in the channel region is identified to be the driving force of device degradation. Since gate current (Ig) consists mainly of electron injection, Ig is found to correlate with device degradation well. Such Ig dependent device degradation suggests that Ig should be examined in evaluating the hot-carrier reliability of LDMOS transistors. [ABSTRACT FROM AUTHOR]

A piezoelectric film has been fabricated by a sol-gel spray technique directly onto an edge of a 2 mm-thick aluminium plate as an integrated ultrasonic transducer and used to detect line defects at a distance using mode converted symmetric and shear horizontal waves at 150°C. [ABSTRACT FROM AUTHOR]

An RF tunable active bandpass filter employing a BaxSr1-xTiO3 (BST) based capacitor is proposed. This filter consists of an active capacitance circuit together with a BST tunable varactor. The active capacitor is made of a field effect transistor that exhibits negative resistance as well as capacitance. BST thin film was deposited by Sol-Gel solution and using the metal-insulator-metal capacitor process. The fabricated capacitor showed capacitance of 2.7–1.5 pF at 1.8 GHz for a maximum applied electric field of 34 V/µm. The measured second-order active bandpass filter showed bandwidth of 100 MHz, insertion loss of+0.48 dB at 1.8 GHz centre frequency and tuning frequency of 220 MHz with the application of 34 V/µm. [ABSTRACT FROM AUTHOR]

A structure for an optimum monopulse feed is proposed at Ku-band using a multimode substrate integrated waveguide (SIW). A 180° directional coupler is employed to realise the in- or out-of-phase feeding mechanism, and an H-plane moder is used to generate the odd and even illumination laws at the aperture. A horn antenna is constructed from the dielectric substrate and three other copper plates to radiate energy effectively. All parts have been fabricated in a normal PCB process. Good agreement between the simulation and measurement is observed, which certifies that this type of SIW monopulse feed is feasible and has good characteristics. [ABSTRACT FROM AUTHOR]

Based on a newly proposed guided wave structure of half-mode substrate integrated waveguide (HMSIW), a narrow-wall double-slot 3 dB directional coupler is proposed, which keeps the advantages of an SIW coupler but with a reduction of nearly one-half in size and better isolation. Simulated results are consistent with the measured data. [ABSTRACT FROM AUTHOR]

The design of RF and millimetre-wave receivers demands low-cost features and compact architecture. Self-oscillating mixers (SOMs) are excellent choices for such a design as both the oscillating source and the mixer are combined in one single device. Moreover, subharmonic operation reduces LO frequency requirements and therefore opens up interesting perspectives for high-end millimetre-wave systems. A fully-balanced third-harmonic SOM structure is presented, operating at 5.8 GHz with high measured conversion gain (max. 8.75 dB) that is used as a frequency-scaled prototype for future millimetre-wave circuits. To the authors' knowledge, this is the first presentation of such a circuit structure. [ABSTRACT FROM AUTHOR]

A low cost high isolation sub-harmonic microwave up-converter is designed using a substrate integrated waveguide (SIW). By employing the cutoff mode concept of SIW, the up-converter has effectively suppressed the output components of local oscillator (LO) frequency and image frequency. Experimental results show an additional 50 dB isolation is achieved with the SIW. [ABSTRACT FROM AUTHOR]

A direct quadrature phase shift keying modulator based on six-port technology is presented. The modulator comprises a six-port circuit, a switch matrix and open and short terminations. Using this modulator, direct phase shift keying modulation was achieved. Six-port technology has the advantage of signal integrity, low power consumption and physical scalability to attain different frequencies of operation and extendibility to M-ary phase shift keying. Experiment results demonstrate performance with an output phase difference from 0.8 to 4.5° and an amplitude difference from 0.5 to 2.7 dB. A data throughput of 200 Mbits was attained. [ABSTRACT FROM AUTHOR]

The optimal angle between the input and output ports of a substrate integrated waveguide (SIW) circular cavity is investigated, and then a compact millimetre-wave SIW circular cavity filter with optimal performance is designed, fabricated with standard PCB process and measured. Measured results show good agreement with the theoretical prediction. [ABSTRACT FROM AUTHOR]

A planar waveguide elliptic filter with a transmission line inserted inverter is proposed. This inline filter based on a substrate integrated waveguide is fabricated by the standard PCB process. Simulated results are compared with measured data and good agreement is reported. [ABSTRACT FROM AUTHOR]