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微波電路期中報告
論文研討:

A High Efficiency and Low Rx-Noise Three Power
ModePower Amplifier for W-CDMA Handsets
作者：

Katsuya Kato Naoko Matsunaga Kenichi Horiguchi
Morishige Hieda and Kazutomi Mori
Mitsubishi Electric Corporation 5-1-1 Ofuna, Kamakura,
Kanagawa, 247-8501 Japan
報告人:
碩研電子一甲 MA130117 陳偉中
Southern Taiwan University
Department of Electronic Engineering
Abstract
 This paper presents a high efficiency and low Receive-band noise power ( RxNoise ) three power mode power amplifier for W-CDMA handsets.
 The number of Switches in output matching circuit and bypass circuit are reduced
to realize high efficiency in high-power mode operation.
 Our developed amplifier achieves 28.25 dBm of high output power with power
added efficiency (PAE) as high as 40% in the high power mode, 17.0 dBm with
23% of PAE in the middle power mode, and 7.0 dBm with 13% in the low power
mode.
Proceedings of APMC 2012, Kaohsiung, Taiwan, Dec. 4-7, 2012
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PROPOSED SWITCHING BYPASS STAGE
POWER AMPLIFIER
 The amplifier consists of high-frequency power transistors (M1,
M2 and M3) which are switched by switches (SWs) corresponding
to the HPM, MPM and LPM.
 In the conventional circuit, the transistor M2 and M3, switches
SW4 and SW5 are on in the HPM. The transistor M2 and, switches
SW2 and SW3 are on in the MPM. The transistor M1 and, switches
SW1, SW2 and SW3 are on in the LPM.
Fig. 1. Block diagram of the conventional stage bypass power
 In the proposed circuit, transistor M2 and M3, switches SW4 are
amplifier
on in the HPM. In HPM, SW6 is also on, and thus M2 operates as a
feedback amplifier. The transistor M2 and, switches SW2 are on in
the MPM. The transistor M1 and, switches SW1, SW2 are on in the
LPM. In MPM and LPM, SW6 is off, and thus the feedback circuit
of M2 is disabled.
Fig. 2. Block diagram of the proposed stage bypass power
amplifier
 First, connected point between bypass circuit and output circuit is
changed from output of the amplifier to corrector of M3 in the
proposed circuit. Second, the feedback circuit with a switch is
employed to the firststage transistor (M2) in the proposed circuit.
Proceedings of APMC 2012, Kaohsiung, Taiwan, Dec. 4-7, 2012
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PERFORMANCE IMPROVEMENT
 A. HPM Efficiency Improvement
 Shows simulated impedances Za and Zb in MPM.
The impedance Za is nearly short in the conventional circuit
configuration.
 The signal from bypass circuit leaks to matching network 6
in the LPM and MPM without SW5. Therefore, the output
switch SW5 must to be employed in the conventional circuit
configuration.
 On the other hand, the impedance Zb is enough high
without the output switch in the proposed circuit configuration.
Therefore, the output switch is not necessary in the proposed
circuit configuration.
Fig. 3. Simulated impedances Za and Zb in the MPM
Proceedings of APMC 2012, Kaohsiung, Taiwan, Dec. 4-7, 2012
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 Shows output circuit loss versus gate width of the
output switch SW5 in Fig. 1. The output circuit loss of
proposed circuit configuration is also shown in Fig.4.
 The simulated output circuit loss of 0.80 dB was
obtained with gate width of 3.8mm in the conventional
circuit configuration.
 Therefore, the proposed circuit configuration can be
reduced output loss by 0.15 dB in the HPM. Therefore,
we can improve HPM efficiency in the proposed
circuit configuration.
Fig. 4. Simulated results circuit loss versus gate width of output
switch SW5 in the conventional circuit configuration and the
simulated output circuit loss of proposed circuit configuration.
Proceedings of APMC 2012, Kaohsiung, Taiwan, Dec. 4-7, 2012
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 B. Rx-Noise Improvement
 Rx-noise and Tx gain decreases with the
decrease of feedback resistance. The feedback
resistance is determined to 900 ohms to meet the
target Tx gain of 28.5dBm, where Rx-noise is
improved to - 137.4 dBm/Hz by 1dB.
 On the other hand, the feedback circuit cannot
be employed to realize Tx gain in MPM and LPM.
Therefore, the SW6 in the Fig2 is employed in
the feedback circuit and is controlled to activate
the feedback circuit only in the HPM to suppress
the Rx-noise in HPM.
Fig. 5. Simulated results of Rx noise and Tx Gain
versus feedback resistance
Proceedings of APMC 2012, Kaohsiung, Taiwan, Dec. 4-7, 2012
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MEASUREMENT RESULT
 (a) and (b) shows the measured PAE and Gain versus output
power, respectively. The supply voltage is 3.4 V, and the input
signal is W-CDMA signal at 1.95 GHz.
 Gain of 27.8 dB, PAE of 40.0% and ACLR of -41.3 dBc
with an output of 28.25 dBm in the HPM.
 Gain of 16.3 dB, PAE of 23.1% and ACLR of -48.0 dBc
with an output of 17.0 dBm 4733B1-04 are achieved in the
MPM.
 Gain of 10.4 dB, PAE of 13.7% and ACLR of -41.0 dBc
with an output of 7.0 dBm are achieved in the LPM.
Fig. 6.Measurement result of proposed circuit at 1950
MHz, WCDMA signal and Vcc=3.4 V. (a) PAE versus
output power, (b)Gain versus output power.
Proceedings of APMC 2012, Kaohsiung, Taiwan, Dec. 4-7, 2012
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 PAE in HPM and LPM was improved with
keeping the PAE in MPM in the proposed circuit.
In addition, the Rx-noise of -136 dBm/Hz (190
MHz offset) is achieved at output power of 28.25
dBm.
Table 1. Measured PAE and Rx-noise of the proposed circuit compared
with and the conventional circuit
Proceedings of APMC 2012, Kaohsiung, Taiwan, Dec. 4-7, 2012
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CONCLUSION
 In this paper, we proposed the three power mode power amplifier for W-CDMA handsets.
The number of switches in output matching circuit and bypass circuit were reduced to realize high
efficiency in the HPM operation by changing the connected point between bypass circuit and
output circuit of the final-stage amplifier.
 The switching feedback circuit wasapplied to the first-stage amplifier to achieve low noise
performance in Rx-band.
 The PA achieved 40% of PAE at 28.25 dBm in the HPM, 23% of PAE at 17.0 dBm in the
MPM and 13% of PAE at 7.0 dBm in the LPM, while satisfying ACLR of less than -40 dBc under
the measurement condition of 1.95 GHz W-CDMA (R99) modulated signal and 3.4 V supply
voltage.
 Good Rx-noise characteristics of - 136 dBm/Hz (190 MHz offset) at 28.25 dBm is achieved by
using the switching feedback circuit.
Proceedings of APMC 2012, Kaohsiung, Taiwan, Dec. 4-7, 2012
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參考文獻
[1] Teeter, D. A., et al.: Average Current Reduction in (W)CDMA Power
Amplifiers, IEEE Radio Frequency Integrated Circuits Symposium
Digest, 429–432 (2006)
[2] Hau, G., et al.: Multi-Mode W-CDMA Power Amplifier Module with
Improved Low-Power Efficiency using Stage- Bypass, IEEE Radio
Frequency Integrated Circuits Symposium Digest, 163–166 (2010)
Proceedings of APMC 2012, Kaohsiung, Taiwan, Dec. 4-7, 2012
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心得
這篇報告中，他們有提出三種功率模式下功率輸出匹配電路和旁通電
路放大器W-CDMA，從輸出匹配電路和旁通電路的開關數量減少，在
HPM操作中來實現高效率的通過而改變旁通電路和輸出電路的最後階
段的放大器之間的連接點。
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