IEEE Transactions on Microwave Theory and Techniques

In this paper, a new frequency-domain formulation of the partial element equivalent circuit (PEEC) model incorporating the concept of generalized complex partial inductance and pure real capacitance is introduced for modeling of 3-D structures, to which the radiation effect is not negligible. Unlike conventional PEEC-based models, the proposed formulation accounts for the radiation effect by intro... View full abstract»

The discrete complex image method (DCIM) has been well-established and widely employed as a tool to compute spatial-domain Green's functions in planar multilayered media. Although the use of the DCIM in conjunction with the method of moments has been quite satisfactory for the efficient analysis of printed structures in layered media, it has not been considered much as a legitimate tool for commer... View full abstract»

We propose a novel parametric macromodeling method for systems described by admittance and impedance representations, which depend on multiple design variables such as geometrical layout or substrate features. It is able to build accurate multivariate macromodels that are stable and passive over the entire design space. Poles and residues are parameterized indirectly. The proposed method is based ... View full abstract»

State-of-the-art integral-equation-based solvers rely on techniques that can perform a dense matrix-vector multiplication in linear complexity. We introduce the H2 matrix as a mathematical framework to enable a highly efficient computation of dense matrices. Under this mathematical framework, as yet, no linear complexity has been established for matrix inversion. In this work, we... View full abstract»

A lattice network with branches made up of open- and short-circuited transmission-line sections is proposed as an equivalent circuit for a wide range of so-called coupled-line filter sections. The proposed lattice equivalent circuits have proven to be an advantageous alternative to the equivalent circuits found in the technical literature (when available) as they are exact, useful in wide frequenc... View full abstract»

This paper presents the first known synthesis method for the design of nonuniform transmission lines (NUTLs) for ultra-wideband (UWB) pulse shaping, which can account for, and partially compensate for, the loss and dispersion present in real transmission lines. Without this compensation, cumulatively increasing distortion occurs in UWB pulse trains generated using NUTLs. The synthesis method novel... View full abstract»

An innovative approach that allows for realization of broadband planar fully integrated 8 × 8 Butler matrices is presented. Coupled-line directional couplers have been utilized, which enable broad operational band. A novel arrangement of the network has been proposed that allows the creation of an entirely planar design having two metallization layers and no interconnections between these l... View full abstract»

An octave bandwidth concept for compact rectangular-to-circular and square-to-circular waveguide transitions based on the use of intermediate octagonal-shaped sections is presented. Apart from its inherent bandwidth capability and spurious mode free operation, this architecture offers some other useful advantages such as easy fabrication, low losses, and extremely short length (less than 0.75 �... View full abstract»

This paper presents tunable balanced bandpass filters with constant fractional bandwidth (FBW) and constant absolute bandwidth (ABW), respectively. The equivalent differential- and common-mode circuits of the proposed filters are analyzed. The differential-mode bandwidths can be maintained constant when the frequency is tuned by selecting proper coupling regions and controlling the external qualit... View full abstract»

This paper presents tunable lumped-element bandstop filters for the UHF-band cognitive radio systems. The two-pole filters are implemented using lumped elements with both single- and back-to-back silicon varactor diodes. The single diode filter tunes from 470 to 730 MHz with a 16-dB rejection bandwidth of 5 MHz and a filter quality factor of 52-65. The back-to-back diode filter tunes from 511 to 7... View full abstract»

This paper presents a high-Q two-pole tunable filter with frequency and bandwidth control. The filter is implemented using suspended-stripline ring resonators and planar RF microelectromechanical systems capacitive networks. A tuning range of 3.7-5.95 GHz with an absolute 1-dB bandwidth of 110±20 MHz (3.6%-1.7% fractional bandwidth) is first demonstrated with an insertion loss <; ... View full abstract»

A cascoded frequency divider (FD) with division number of 4 and ultra-wide locking range is presented in this paper. The proposed FD consists of a divide-by-2 (D2) injection-locked frequency divider (ILFD) core and a D2 source-injection current mode logic (SICML) divider. After the cascoded integration of ILFD and SICML, the removal of transconductance and buffer stages can lower the dc power cons... View full abstract»

A GaAs monolithic K -band left-handed frequency multiplier based on a composite right/left-handed coplanar-waveguide transmission line (TL), periodically distributed series planar Schottky varactor diode, and shunt rectangle spiral inductor has been successfully designed and fabricated. The anomalous dispersion of the left-handed TL and strong nonlinearity of the Schottky varactor are combi... View full abstract»

This paper presents the design and characterization of two resistive mixers integrated with a double-slot antenna in a 100-nm GaAs mHEMT technology. With RF frequency varying from 185 to 202 GHz, a typical conversion loss (L c) of 8.0 dB is measured for the single-ended mixer and a typical L c of 12.2 dB is obtained from one of the two IF outputs for the single-balanced mixer. Each m... View full abstract»

In a wideband receiver, higher frequency channels may be converted to the frequency of a desired signal by a harmonic mixing mechanism. To alleviate this issue, this paper proposes a topology, called the classBlike converter, to achieve high harmonic mixing rejection in frequency translation without any filtering. The converter is based on a linear commutation with a sinusoidal local oscillator fo... View full abstract»

A low-power, high-gain (HG), and low-noise (LN) CMOS distributed amplifier (DA) using cascaded gain cell, formed by an inductively parallel-peaking cascode-stage with a low-Q RLC load and an inductively series-peaking common-source stage, is proposed. Flat and high S21 and flat and low noise figure (NF) are achieved simultaneously by adopting a slightly under-damped Q View full abstract»

This paper presents a SiGe envelope-tracking (ET) cascode power amplifier (PA) with an integrated CMOS envelope modulator for mobile WiMAX and 3GPP long-term evolution (LTE) transmitters (TXs). The entire ET-based RF PA system delivers the linear output power of 22.3/24.3 dBm with the overall power-added efficiency of 33%/42% at 2.4 GHz for the WiMAX 64 quadrature amplitude modulation (64QAM) and ... View full abstract»

A design methodology for a concurrent dual-band Doherty power amplifier (PA) with frequency-dependent backoff power ranges is presented in this paper. Based on a dual-band T-shaped network and a coupled line network, different dual-band components needed in Doherty PA topology, including a 3-dB branch-line coupler, an offset line, and a quarter-wavelength transformer, are developed. Two prototypes... View full abstract»

This paper presents a novel 2-D digital-predistortion (2-D-DPD) technique that is applicable for linearization of concurrent dual-band transmitters. This technique uses a unique way for distortion compensation and linearization of dual-band transmitters by selecting, characterizing, and applying predistortion in each band separately. Compared to conventional linearization techniques, this 2-D-DPD ... View full abstract»

This paper deals with a systematic evaluation of the antenna impact on the gauging accuracy of industrial radar level measurements for process automation. By this means, a framework is provided by which the antenna parameters of major influence on the gauging accuracy can be identified. Guidelines are given to what extent an improvement of these parameters results in a measurable accuracy increase... View full abstract»