Intermodulation in heterojunction bipolar transistors

Maas, S.A.; Nelson, B.; Tait, D.

doi:10.1109/mwsym.1991.146932

Cited by 15 publications

(22 citation statements)

References 7 publications

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“…GaAs HBTs also offer unusually high linearity at relatively low levels of dc bias power [1]. [2] showed that, in the baseemitter junction, the intermodulation (IM) current generated in the resistive part is partially cancelled by the IM current generated in the capacitive part, and that this phenomenon is largely responsible for the unusually good IM performance of these devices. [3], [4] also showed through analysis that the total nonlinear currents generated by the base-emitter junction, I E and the base-collector junction, I C (not including C BC ) partially cancelled resulting in high linear characteristics of HBTs.…”

Section: Introductionmentioning

confidence: 99%

High-linearity two-watt power amplifier for multiband wireless applications

Faiz

Earles

Hou

et al. 2012

2012 Proceedings of IEEE Southeastcon

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Amplifiers in the final stages of wireless transmitters boost the power level of the up-converted signals, but the ultimate power level is not same for all transmitters. One specific amplifier can be used as a driver in a cellular base station or as last stage in applications like a pico-cell. However, the amplifier has to meet the stringent linearity requirement imposed by these different standards. In this paper, we present a highly linear single stage two watt power amplifier in GaAs HBT process. The amplifier can be externally matched at the input and output, thus provides flexibility to optimize it across a specific frequency band of interest between 400 MHz and 2700 MHz. The design includes a novel approach of utilizing the nonlinear base-collector and base-emitter diode capacitances of a transistor biased in the saturation region to improve the linearity of the amplifier. The transistor provides a nonlinear feedback path between the output and input of the amplifier and thus minimizes the third order intermodulation distortion (IM3) component.

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Section: Introductionmentioning

confidence: 99%

High-linearity two-watt power amplifier for multiband wireless applications

Faiz

Earles

Hou

et al. 2012

2012 Proceedings of IEEE Southeastcon

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“…Hence, the challenge lies in developing an HBT model which covers simultaneously de, small-signal ac, and microwave large-signal applications. Much work has been done in explaining HBT behavior based on an equivalent circuit approach [7,6,5,18). There are different approaches, for example Wang et al [5) undertook involved simulation based on a SPICE model.…”

Section: Introductionmentioning

confidence: 99%

“…They basically focused on cancellation among currents induced by B-E and B-C junction. Maas and Nelson [6] suggested an interesting and simple model for the current gain which automatically includes the gain roll-off at higher frequencies. Brazil et al [7] proposed a model which differs from common models mainly in that the base region is split into several nodes and that two diodes with different charachteristics simulate lb and le independently.…”

Section: Introductionmentioning

confidence: 99%

Nonlinearities in the Base Emitter Junction of Heterojunction Bipolar Transistors

Woywode¹

2000

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The nonlinear behaviour of the base emitter junction in HBTs is investigated.Nonlinearities cause troublesome distortion and intermodulation of signals and raise the bit error rate. They are therefore a key issue in microwave communication systems.Hewlett-Packard's Microwave Design System (MDS) software package has been used to simulate these phenomena. The simulation results are verified by an analytical method called nonlinear current method which is a derivative of the Volterra series approach. With the aid of this method new analytical expressions are derived that provide insight into the subtleties of nonlinear phenomena. These expressions are evaluated by the program MAPLE and subsequently compared with the MDS results. Two different models for the B-E junction are juxtaposed. The derived equations reveal the identity and correspondence between the two models.Finally, this thesis also addresses harmonic balance simulation which is the type of simulation MDS employs to simulate nonlinear circuits.

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“…Excellent results in IP3 and adjacent channel power ratio (ACPR) were shown in [1][2][3] through linearity characterizations of GaAs and InP-based HBTs. [4] showed that, in the base-emitter junction, the intermodulation (IM) current generated in the resistive part is partially cancelled by the IM current generated in the capacitive part, and that this phenomenon is largely responsible for the unusually good IM performance of these devices. [5], [6] also showed through analysis that the total nonlinear currents generated by the baseemitter junction, I E and the base-collector junction, I C (not including C BC ) partially cancelled resulting in high linear characteristics of HBTs.…”

mentioning

confidence: 99%

A novel circuit to achieve high linearity in power amplifiers for WCDMA cellular base transceiver stations

Faiz

Earles

Hou

et al. 2012

WAMICON 2012 IEEE Wireless &Amp; Microwave Technology Conference

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This paper presents a novel circuit to minimize the third order intermodulation distortion component and thus improves the linearity of power amplifiers. The circuit utilizes the nonlinear base-collector and base-emitter diode capacitances of a transistor biased in the saturation region to provide a nonlinear feedback path between the output and input of the amplifier. This concept was implemented in the design of a two watt power amplifier in InGaP/GaAs heterojunction bipolar transistor process. The design demonstrated 51 dBm of output third order intercept point at 17 dBm/tone output power level at 2140 MHz in the WCDMA band. The output P1dB was measured to be about 32 dBm. The amplifier is externally matched, thus provides flexibility to optimize the amplifier across a specific frequency band of interest between 400 MHz and 2700 MHz.

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Intermodulation in heterojunction bipolar transistors

Cited by 15 publications

References 7 publications

High-linearity two-watt power amplifier for multiband wireless applications

High-linearity two-watt power amplifier for multiband wireless applications

Nonlinearities in the Base Emitter Junction of Heterojunction Bipolar Transistors

A novel circuit to achieve high linearity in power amplifiers for WCDMA cellular base transceiver stations

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