A low third order intermodulation amplifier with harmonic feedback circuitry

Moazzam, M.R.; Aitchison, C.S.

doi:10.1109/mwsym.1996.511065

Cited by 55 publications

(19 citation statements)

References 4 publications

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“…If we now add to the amplifier input voltage components at the second harmonic of the two input frequencies, we can write (4) where the harmonic frequencies have amplitudes and phases and , respectively. The expression for the IM3 drain current at the frequency is then given by (5) when other small terms are neglected. A similar expression is obtained for the IM3 product of the drain current at .…”

Section: Theorymentioning

confidence: 99%

Improvement of third-order intermodulation product of RF and microwave amplifiers by injection

Aitchison

Mbabele

Moazzam

et al. 2001

IEEE Trans. Microwave Theory Techn.

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101

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Abstract-This paper discusses the improvement in the third-order intermodulation product (IM3) performance obtainable from RF and microwave amplifiers by two alternative injection techniques. The first is the addition to the amplifier input of the second harmonics of the input spectrum and the second is the addition to the amplifier input of the difference frequencies between the spectral components of the input signal. Both techniques are considered in theory, by simulation and in practice. Both techniques give useful improvements in two-tone IM3 performance. The second harmonic technique reduced the IM3 level by 43 dB in an amplifier at 835 MHz. The difference-frequency technique gave a reduction of 48 dB in an amplifier at 880 MHz. The difference-frequency technique also gives a greater improvement for complex spectra signals.

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Section: Theorymentioning

confidence: 99%

Improvement of third-order intermodulation product of RF and microwave amplifiers by injection

Aitchison

Mbabele

Moazzam

et al. 2001

IEEE Trans. Microwave Theory Techn.

Self Cite

101

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show abstract

“…Moreover, harmonic injection techniques have been proposed to optimise linearity performances [14]. In any case, however, linearization techniques, such as feedback, feed forward [22], or predistortion [9][10][11][12][13][14][15], could be used to further improve the linearity. Feedback is good for audio power amplifiers, but for RF power amplifiers the stability and efficiency can be compromised.…”

Section: Introductionmentioning

confidence: 99%

A Contribution to Linearity Improvement of a Highly Efficient Pa for Wimax Applications

Maazouzi¹,

Mediavilla²,

Colantonio³

2011

PIER

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Abstract-This paper describes the design of a highly efficient and linear GaN HEMT power amplifier which may be used in WiMAX application. To improve linearity of highly efficient power amplifiers, a technique using diodes in the gate DC path was applied to TL and 2HT amplifier. This solution using diodes offers a good manner to improve linearity near saturation zone compared to the approach using only a DC gate resistor for TL (tuned load) case as well as for 2HT (second harmonic tuning approach). A 2.5 GHz 2HT power amplifier circuit was built, and measured data confirm the linearity improvement, particularly near saturation zone, as predicted by simulation, maintaining higher power performances. An output power of 36.8 dBm has been measured with an associated power added efficiency of 46.5% and carrier to third order intermodulation (C/I3) of 53.4 dBc. A 2HT PA also exhibits good performances across the full (2.3-2.7) GHz band. An output power ranging from (35-36.9) dBm with an associated gain of 12.9 ± 0.9 and a power added efficiency ranging from (40-46)% are measured across the full (2.3-2.7) GHz band.

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“…The expression for the injection of the second-order IM signals ,at frequencies which are the sum of the fundamental signal frequencies is: vj,, = v,, Cos(Wlt)+v,2 C0s(w2t)+Vo3Cos (w,t) + V i I Z c4J4 t + w2t + (Po,, )+ 4 % t + 0 3 t + (Po,, +VOl3 co.4w + 0 3 t + (Pw,, 1 (4) where the injected signals (01+9), (e++%) and (ol+y) have amplitudes VoI2, VWz3 and V, and phases (pol,, go,, and respectively. The additional signals at the second kind IM3 frequencies at output of the amplifier are the results of interaction between the source signals (aI,% and 03) and the injected IM2 signals.…”

Section: Discussionmentioning

confidence: 99%

“…Simulated results referring to the designed phase shifter and variable attenuator show almost constant characteristics of the relative phase shift over frequency range 5-5.2 GHz and straight attenuation characteristics for 5-5. 4 GHz frequency range. …”

Section: Discussionmentioning

confidence: 99%

A multicarrier amplifier design linearized trough second harmonics and second-order IM feedback

Milovanović¹,

Males-Ilic²,

Budimir³

5th International Conference on Telecommunications in Modern Satellite, Cable and Broadcasting Service. TELSIKS 2001. Proceedin

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-A novel linearisation technique for reduction in the first and second kind of the third-order intermodulation products was applied in this paper. The second harmonics and second-order intermodulation products are led from the output to the input of a power amplifier through a feedback loop. The power amplifier including the feedback loop components (bandpass filter, phase shifter and attenuator) was designed as a hybrid microwave integrated circuit by using program ADS. The phase and amplitude of the loop signals are the adjustable parameters. Therefore, a voltage that controls a phase shift of the phase shifter and a control current of a PIN diode in the attenuator circuit were optimised to obtain a reduction in the third-order intermodulation distortion. For three fundamental signals at the power amplifier input, the lowest improvement of 13 dB for the fist and 18 dB for the second kind of the thirdorder intermodulation product levels was achieved.Keyworcls -power amplifier, third-order intermodulation, linearization technique, phase shifter, attenuator, bandpass filter.

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A low third order intermodulation amplifier with harmonic feedback circuitry

Cited by 55 publications

References 4 publications

Improvement of third-order intermodulation product of RF and microwave amplifiers by injection

Improvement of third-order intermodulation product of RF and microwave amplifiers by injection

A Contribution to Linearity Improvement of a Highly Efficient Pa for Wimax Applications

A multicarrier amplifier design linearized trough second harmonics and second-order IM feedback

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