IEEE Microwave and Wireless Components Letters

A 32:1 static frequency divider consisting of five stages of 2:1 dividers using current mode logic (CML) was fabricated in a 130-nm bulk complementary metal-oxide semiconductor (CMOS) logic process. By optimizing transistors size, high operating speed is achieved with limited power consumption. For an input power of 0dBm, the 32:1 divider operates up to 26GHz with a 1.5-V supply voltage. The whole... View full abstract»

This letter presents a 0.13-μm CMOS frequency divider realized with an injection-locking ring oscillator. This topology can achieve a larger input frequency range and better phase accuracy with respect to injection-locking LC oscillators, because of the smoother slope of the loop gain phase-frequency plot. Post layout simulations show that the circuit is able to divide an input signal span... View full abstract»

A Ka-band monolithic microwave integrated circuit (MMIC) oscillator was implemented by using a coplanar waveguide photonic bandgap (PBG) resonator and a 0.1-μm GaAs pseudomorphic high electron mobility transistor. A coplanar labyrinthine one-dimensional PBG resonator was used for reduction in MMIC size. The fabricated MMIC oscillator had an output power of 6.5dBm at 30.3GHz and a free-runn... View full abstract»

A SiC Clapp oscillator fabricated on an alumina substrate with chip capacitors and spiral inductors is designed for high-temperature operation at 1GHz. The oscillator operated from 30°C to 200°C with an output power of 21.8dBm at 1GHz and 200°C. The efficiency at 200° C is 15%. The frequency variation over the temperature range is less than 0.5%. View full abstract»

A fully integrated back-gate transformer feedback CMOS differential voltage-controlled oscillator (VCO) has been designed for high-frequency and low-phase noise operation using an 0.18-μm CMOS process. The proposed VCO topology utilizes the monolithic transformer feedback configuration from the drain to the back-gate of the switching transistors in VCO. The VCO operating in an 11-GHz band ... View full abstract»

This paper presents current reused voltage controlled oscillator (VCO) topologies by stacking switching transistors in series like a cascode. The VCOs can operate with only half the amount of dc current compared to those of the conventional VCO topologies. Fabricated in 0.18-μm CMOS process, a differential VCO operates in a 2.1-GHz band with a phase noise of -110dBc/Hz at 1-MHz offset, and... View full abstract»

This letter describes a ferroelectric thin-film based varactor shunt switch, for microwave and millimeterwave switching applications. Our implementation is based on a coplanar waveguide transmission line shunted by a ferroelectric varactor. The concept of switching ON and OFF is based on the dielectric tunability of the ferroelectric barium strontium titanium oxide (BST) thin-films. From experimen... View full abstract»

This letter presents the design and fabrication of a Ku-band differential-mode voltage-controlled oscillator (VCO) with extremely low power consumption and good phase noise characteristics based on a monolithic InP-based resonant tunneling diode/heterojunction bipolar transistor (RTD)/(HBT) technology. In order to reduce the power consumption, an InP-based RTD is used for microwave power generatio... View full abstract»

This letter presents a fully integrated distributed amplifier in a standard 0.18-μm CMOS technology. By employing a nonuniform architecture for the synthetic transmission lines, the proposed distributed amplifier exhibits enhanced performance in terms of gain and bandwidth. Drawing a dc current of 45mA from a 2.2-V supply voltage, the fabricated circuit exhibits 9.5-dB pass-band gain with ... View full abstract»

The linearity of a 30-W high-power Doherty amplifier is optimized using post-distortion compensation. A balanced high-power Doherty amplifier using two push-pull laterally-diffused metal-oxide semiconductor (LDMOS) field-effect transistors (FETs) is linearized by optimum adjustment of the peaking compensation line, shunt capacitors, and gate biases. The measured results of an optimized Doherty amp... View full abstract»

A 25-GHz monolithic voltage controlled oscillator (VCO) has been designed and fabricated in a commercial InGaP/GaAs heterojunction bipolar transistor (HBT) process. This balanced VCO has a novel topology using a feedback π-network and a common-emitter transistor configuration. Ultra-low phase noise is achieved: -106 dBc/Hz and -130 dBc/Hz at 100kHz and 1-MHz offset frequency, respectively. To t... View full abstract»

A divide-by-1/1.5 divider cell using a dual edge-trigger technique is proposed. Based on this divider cell, a dual-mode programmable divide-by-X circuit is demonstrated in 0.18-μm CMOS technology, where X=P or P.5 in one mode and 2P or 2P+1 in the other mode with P=128-255. When operated in the divide-by-2P/2P+1 mode, this circuit outputs a signal with 50% duty cycle. Theoretically, P can ... View full abstract»

A very low minimum noise figure (NFmin) of 1.2 dB and a high associated gain of 12.8 dB at 10 GHz were measured for six-finger, 0.18-μm radio frequency (RF) metal-oxide semiconductor field-effect transistors mounted on insulating plastic following substrate-thinning (/spl sim/30 μm) and wafer transfer. Before this process, the devices had a slightly better RF performance... View full abstract»

The phase shifters based on the synchronization of an oscillator to the input signal enable low consumption, low cost, and small size. However, the difficulties for an accurate design, associated to the complexity of the operation regime, limit their application to communication systems. Here, a technique is presented for the nonlinear synthesis of oscillator-based phase shifters. The technique pr... View full abstract»

A power amplifier with a compact output matching network and a high average operating efficiency owing to its control circuits which enable the dynamic control of the quiescent current is presented. The microwave monolithic integrated circuit of the power amplifier was designed and implemented, in order to verify the output matching network and control circuits for the 1.88-GHz band. The power-add... View full abstract»

A novel and compact ultra-wideband (UWB) microstrip-fed monopole antenna having frequency band notch function is presented. To increase the impedance bandwidth of an antenna, a narrow slit is used. By inserting a modified inverted U-slot on the proposed antenna, the frequency band notch characteristic is obtained. The designed antenna satisfies the voltage standing wave ratio requirement of less t... View full abstract»

In this letter, it is the first time to implement the theory of Maxwellian circuits (TMC) to the printed spiral antennas. First, the Maxwellian circuit models (MCM) for the printed spiral antennas are established through two independent sets of full-wave solutions of current and scalar potential distributions. In this stage, a relationship between the scalar potential and voltage is proposed to sa... View full abstract»

An effective numerical technique employing the precorrected-fast Fourier transform (P-FFT) technique based on the method-of-moments (MoM) is presented to study the scattering from wide-slot antennas fed by waveguides with arbitrary terminations. As the Rao-Wilton-Glisson (RWG) functions are used as the basis and testing functions, the magnetic currents with arbitrary slot directions are considered... View full abstract»

A miniaturized Wilkinson power divider implemented in a standard 0.18-μm CMOS process is presented in this letter. By using active inductors for the circuit implementation, a significant area reduction can be achieved due to the absence of distributed components and spiral inductors. The power divider is designed at a center frequency of 4.5GHz for equal power dividing with all ports match... View full abstract»

In this letter, a closed-form integral model is presented for the rectangular micromachined spiral inductor. The Kramers-Kronig relations provide an elegant theory to describe the inductor behavior without having complicated geometric analysis. Simulation and measurement results validate that the model can provide satisfactory prediction to the inductance of on-chip freely-suspended spiral inducto... View full abstract»

Compact, broadband, and low-cost reflectometry is important for array-based microwave imaging and sensing applications in biology and medicine. To achieve broadband performance, we use cascaded bridged-T attenuators incorporating mixers to replace directional couplers in a new reflectometer design. In this letter, we present the design of the reflectometer and the associated calibration technique.... View full abstract»

This letter describes the design of a novel transmission line, where characteristic impedance can be adjusted electronically, and its application to a phase shifter. A tunable transmission line enables microwave circuit designers to have flexibility and better return loss which can enhance its tuning range. A UHF band distributed analog phase shifter, as well as a tunable transmission line, is pre... View full abstract»

A planar four-pole linear phase filter centered at 10GHz based on substrate integrated waveguide (SIW) is proposed. The filter is composed of four side-by-side horizontally oriented SIW cavities, which are coupled in turn by evanescent waveguide sections with three direct coupling and one cross coupling between the first and fourth SIW cavities. The SIW cavities are fed by microstrips through coup... View full abstract»