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The compact coupled-line bandpass filters with two capacitive cross-couplings to create four transmission zeros are proposed. The locations of transmission zeros can be adjusted by varying the values of cross-coupled capacitances so as to improve the filter selectivity. To demonstrate the concept of multiple cross-couplings, a 4th-order microstrip coupled-line bandpass filter with four transmission...
In this work, using a microstrip line employing periodically perforated ground metal (PPGM) with single-sided via holes on GaAs MMIC, highly miniaturized and broadband on-chip passive components were developed for application to GaAs MMIC. The passive components employing PPGM were highly miniaturized compared with conventional ones.
An AlGaN/GaN high electron mobility transistor (HEMT) device based on a novel inner field- plate (IFP) structure is proposed and fabricated. At an optimum bias condition of the inner field-plate (VIFP), the gate leakage current of the device has been reduced by more than 15%. In addition, the microwave performance has been found to be improved considerably with increased cut-off frequencies of fT...
We have developed an evolutional equipment using "power spectrum method" capable of precisely measuring the delay time and level of delay waves with delays of 1 symbol (1ms) or longer, for use in the measurement of delay profiles in single-frequency networks (SFNs) used for terrestrial digital television broadcasting.
Thermal resistance of a 3 GHz power amplifier MMIC has been calculated with finite element (FE) analyses. Through comparative FE analyses it has been found that a carrier for infrared (IR) scan test should have high thermal conductivity if it is for measuring thermal resistance of an MMIC only. IR scan results showed that the FE analysis provided temperature distribution quite close to the real and,...
New differential stacked spiral inductors were employed in our design of VCOs fabricated using the CMOS 0.18 mum technology in this paper. The frequency tuning range of these VCOs were extended significantly, and the measured oscillation frequencies cover from 1.69 to 2.1375 GHz, with 23.3% tuning range and phase noise about -118.41 dBc/Hz at 1 MHz theoretically. The core current of these VCOs is...
On the very last months, gallium nitride (GaN) technology has made a remarked breakthrough in the world of microwave electronics with the announcement of commercially available power transistors. Those striking news follow several publicized results that had been published since few years. How this GaN technology would impact space- borne units is now a priority concern. Although the power capability...
This paper demonstrates a circuit technique to improve the phase noise of a GHz-range CMOS differential LC VCO. The VCO has two on- chip transformers; primary of each transformer is used as an inductor of the LC tank. A signal current, whose frequency is the same and phase is 90 degrees in advance of the primary coil, is produced in the secondary coil so that the series resistance of the primary coil...
In this paper, we describe the recent progress of high power GaN high electron mobility transistors (GaN HEMTs) for wireless base station application. First we introduce device technology and RF power performance of GaN HEMTs. Next, we discuss their reliability and cost issues which are great important for practical applications. As an example, GaN HEMTs on a low-cost conductive 3-inch SiC substrate...
A printed antenna is presented that is realized on an Indium Phosphide wafer. The antenna uses aperture coupling between a CPW feed line and a parasitic patch, with the substrates layers in a hi-lo configuration. The antenna exhibits a measured impedance bandwidth of 12%, and a gain of 6plusmn2 dBi within this bandwidth. Applications for this efficient, broadband InP based antenna include MMIC and...
A compact ultrawide-band (UWB) integrated circuit package antenna (ICPA) with a small footprint of 6.18times11.35 mm2 has been designed for the fist time in a 20times10times1.2 mm3 low-temperature cofired ceramic (LTCC) package format with feeding network and the transceiver chip loaded. The chip-package co-EM simulation method is used. A design procedure based on the return loss parameter is illustrated...
In this paper, shunt open stubs are used to suppress second to sixth harmonics of a planar rat-race coupler. Besides, the fabricated coupler occupies only 31.3% area of a conventional one. The coupler characteristics remain comparable to that of a conventional coupler at the fundamental operating frequency. Design guide lines are also provided.
This paper presents the design of an ultra wideband (UWB) low noise amplifier (LNA), operated in the range from 3.1 to 10.6 GHz, with noise canceling technology. A two-stage topology is adopted to implement an LNA based on the TSMC 0.18-um process. The first stage is the cascode configuration that is used to exploits negative feedback to enhance the bandwidth. In order to achieve simultaneously output...
This paper presents a review of the recent quasi-invariant single-parameter criterion for linear two-port unconditional stability. The criterion involves a symmetrical parameter Kt, which is invariant under arbitrary lossless termination and reactive matching at either port when unconditional stability exists or |Delta| les 1. This parameter is hereby derived from the classical matrix invariants and...
This paper discusses the effects of the structure of inductors and capacitors on the performance of LNA circuits. Using a 0.25 μm CMOS process, several LNA circuits employing the common-source topology with cascode configuration are designed, implemented, fabricated, and tested. The gain, isolation, and matching characteristics of LNA circuits implemented using different inductor and capacitor structures...
In this paper, on-wafer level packaging technology for RF MEMS is described, and then a novel packaging design for RF MEMS devices with different fabrication technology at millimeter-wave band is presented. The discussed RF MEMS devices on naked wafer includes a MEMS filter and a distributed MEMS transmission line (DMTL) phase shifter, which are fabricated using LIGA and micromachined technology,...
In this paper, a novel compact internal wide-band planar inverted F-antenna (PIFA) is presented. The proposed antenna consists of a main patch with stubs and folded plate and occupies a total volume of 36 times 16 times 6 mm3. The dual bands characteristic can be achieved by changing the length of a main patch. A wide impedance bandwidth characteristic was obtained by optimizing the length of folded...
A new kind of information carrying technology is proposed on the platform of a circularly-polarized Van Atta retrodirective array. Similar to the phase conjugated array but with lower design complexity, the proposed array exhibits retrodirectivity and can transmit information from the base station to the interrogator. In this paper, a dual-circularly-polarized antenna array that can isolate the incoming...
This paper presents an ultra- wideband (UWB) bandpass filter using broadside- coupled structure and combining shunt stub with chip capacitor to improve the out-band performance of the filter, particularly at the low frequency end. The measured results show that combining the filter and the shunt stub circuit produces an UWB bandpass filter with good performance, including the low insertion loss about...
This is the first report of the traveling wave SPDT switch using the fully distributed FET (FD-FET). The broadband characteristics were successfully obtained over more than an octave frequency range from Ka to W bands for the millimeter-wave applications. From 38 to 80 GHz, the low insertion loss of less than 2.1 dB, and the high isolation of better than 25.5 dB, were achieved by using the AlGaAs/InGaAs...
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