IEEE Transactions on Microwave Theory and Techniques

A compressive receiver (CR) is presented utilizing a composite right/left-handed (CRLH) dispersive delay line (DDL) for analog signal processing applications. The CRLH DDL offers advantages such as arbitrary frequency of operation and wide bandwidth, filling a gap with competing DDL technologies. The presented CR system utilizes an impulse-driven CRLH DDL and mixer inversion for chirp generation r... View full abstract»

A theoretical and practical investigation of polymer composites including paint layers as radomes for automotive long-range radar systems operating at 76.5 GHz is carried out. The materials in focus of this research are metallic base paints with a high concentration of metal, and hence, a high dielectric constant. A multilayered free-space measurement technique is presented to derive the dielectri... View full abstract»

A resistive feedback differential low-noise amplifier (LNA) with enhanced loop gain is implemented as a part of a digital TV (DTV) tuner using a 0.18-mum CMOS process. A voltage buffer having higher gain, higher linearity, and lower noise figure (NF) than those of the conventional differential source follower (DSF), which is called the differential hybrid voltage buffer (DHVB) in this paper, is de... View full abstract»

A comparison between the RF performance of vertical and lateral power MOSFETs is presented. The role of each parasitic parameter in the assessment of the power gain, 1-dB compression point, efficiency, stability, and output matching is evaluated quantitatively using new analytical expressions derived from a ten-element model. This study reveals that the contribution of the parasitic parameter on d... View full abstract»

A class-E power amplifier is proposed in this study. It uses both nMOS and pMOS as switching devices to reduce the voltage stress of each transistor. A voltage-combining scheme with nMOS and pMOS is proposed, and a transformer is designed using this scheme. The power amplifier is implemented in a 0.18-mum RF CMOS process. Measurements show a maximum output power of 30.2 dBm with 36.8% power-added ... View full abstract»

A 33-dBm P 0.1-dB single-pole double-throw antenna switch is designed and implemented using a standard 0.18-mum CMOS process at 1.8 GHz. An analysis shows a relation between parasitic junction capacitors and substrate resistance for low insertion loss (IL). The power-handling capability of the switch was also investigated through the voltage dividing mechanism through the substrate in the c... View full abstract»

CMOS passive mixer linearity is analyzed using a Volterra-series analysis and closed-form expressions for IIP2, two-tone IIP3, and cross-modulation IIP3 are presented, exhibiting dependence upon the mixer source and load impedances. Design guidelines are suggested for improving the mixer linearity performance. Accurate expressions are presented for the input impeda... View full abstract»

In order to combat high peak-to-average power ratio and poor power efficiency, drain modulated polar transmitter architectures have been proposed for orthogonal frequency-division multiplexing (OFDM) systems. However, this type of power amplifier architecture suffers from poor linearity in the low amplitude region, which often causes significant distortion to the system. In this paper, we propose ... View full abstract»

In a spatially dispersive medium, the electric dipole moment of an inclusion cannot be related to the macroscopic electric field through a local relation. Several recent works have emphasized the role of spatial dispersion in wire media, and demonstrated that arrays of parallel metallic wires may behave very differently from a uniaxial local material with negative permittivity. Here, we investigat... View full abstract»

In this paper, a nonlocal homogenization model is proposed for the analysis of the spectrum of natural modes on sub-wavelength mushroom-type high-impedance surfaces composed of a capacitive grid connected to a grounded wire-medium (WM) slab. Modal characteristics of mushroom structures are studied in conjunction with the surface-wave and leaky-wave propagation on WM slabs based on local and nonloc... View full abstract»

We propose to model periodic structures by equivalent multiconductor transmission lines (MTLs). The developed technique is based on a multimodal representation of the periodic structure unit cell, such as required for periodically loaded MTLs and periodically loaded waveguides with higher order evanescent mode interaction between cells. Compared to commonly employed periodic structure analyses whi... View full abstract»

This paper presents a novel technique to develop combined neural network and transfer function models for parametric modeling of passive components. In this technique, the neural network is trained to map geometrical variables onto coefficients of transfer functions. A major advance is achieved in resolving the discontinuity problem of numerical solutions of the coefficients with respect to the ge... View full abstract»

The filtering characteristics of a transmission line loaded at regular intervals with closely spaced shorted stubs are investigated theoretically, experimentally, and by means of rigorous electromagnetic simulations. It is shown that this periodic structure exhibits waveguide-like behavior with a first passband whose width is a function of the characteristic impedance and pitch of the stubs. It is... View full abstract»

This paper introduces a micromachined thick single-metal-layer high aspect-ratio coplanar waveguide (CPW) wideband bandpass filter with compact unit cells based on the electromagnetic bandgap (EBG) concept. The filter is miniaturized as a result of using the EBG concept in design, and also by realizing high aspect-ratio structures with polymer-based deep X-ray lithography fabrication. Cascaded uni... View full abstract»

A novel axially symmetric oversized coaxial waveguide power combiner/divider, which utilizes a planar probe array to transform multiway input to a central oversized coaxial waveguide, is presented in this paper. The use of a coaxial waveguide allows standard transverse electromagnetic design theory to be used, and the characteristics of the coaxial taper transition and the planar probe array are a... View full abstract»

A reconfigurable tuner is demonstrated by using a low-loss shielded coplanar waveguide transmission line periodically loaded with CMOS transistor switches in series with capacitors. The switch-capacitor combination is used to change the local impedance of the transmission line in a binary fashion. It achieves a higher capacitance ratio (by 60%), less transmission loss (by 40%), higher quality fact... View full abstract»

In this paper, a new composite right/left-handed transmission line (CRLH-TL) with equilateral slots is proposed for efficiency-improved zeroth-order resonant antennas. A 1-D infinitesimal equivalent transmission line circuit model is derived, and the characteristic impedance and dispersive relation are theoretically computed. Based on the isotropic arranged unit cells of the slot-loaded composite ... View full abstract»

This paper presents several micro-coaxial broadband 2 : 1 Wilkinson power dividers operating from 2 to 22 GHz, a 11 : 1 bandwidth. Circuits are fabricated on silicon with PolyStrata technology, and are implemented with 650 mum times 400 mum air-supported micro-coaxial lines. The measured isolation between the output ports is greater than 11 dB and the return loss at each port is more than 13 dB ov... View full abstract»

A 2-D electrical filter is introduced that is compatible with today's conventional integrated circuit processes. The rich 2-D propagation properties of the medium are used to introduce a novel high quality factor filter called an electrical prism. The proposed filter shows a quality factor much larger than the quality factor of the individual components at high millimeter-wave and terahertz... View full abstract»

This paper derives a unified thru, reflect, match (TRL) and line, reflect, match (LRM) calibration algorithm using S-parameters instead of traditional T-parameters. The advantage of this approach is that we get a solution where the LRM is an integral part of the TRL algorithm. The expression for the transmission coefficient of the line standard has the convenient property that, in many cases, the ... View full abstract»

This paper presents a novel SPICE compatible partial-element equivalent-circuit (PEEC) model for general linear medium. In this new model, the magnetized current in conductive magnet and fictitious magnetized current through the magnetic interface are considered, as well as conduction current in conductor and polarization currents in a dielectric, to model the magnetization and conduction loss eff... View full abstract»

In this paper, improved transponders with multistage automatic gain control (AGC) for radio-over-fiber-based distributed antenna systems are presented. Error vector magnitude performance measurements for both uplink and downlink paths are carried out to verify the feasibility of applying this system for IEEE 802.11g signal transmission. The developed conventional radio-over-fiber system shows its ... View full abstract»

This paper presents an approach to RF microelectromechanical systems (MEMS) capacitive shunt switch design from K-band up to W-band based on the scalability of the RF MEMS switch with frequency. The parameters of the switch's equivalent-circuit model also follow scaling rules. The measurement results of the fabricated switches show an excellent agreement with simulations that allow t... View full abstract»