I. INTRODUCTION. Recently, E-band wireless communication systems are expected to be newly used in fixed networks for fiber extension or 3G/4G, LTE, and ...
Proceedings of the 8th European Microwave Integrated Circuits Conference
E-Band Receiver and Transmitter Modules With Simply Reflow-Soldered 3-D WLCSP MMIC’s K. Tsukashima, M. Kubota, O. Baba, T. Kawasaki, A. Yonamine, T. Tokumitsu
Y. Hasegawa Sumitomo Electric Device Innovations Inc, 1000 Kamisukiawara, Showa-cho, Nakakoma-gun, Yamanashi, Japan
Sumitomo Electric Industries LTD, 1, Taya-cho, Sakae-ku, Yokohama, Kanagawa, Japan
symmetrical in the node allocation to simplify the PCB design for power combining. The RX module consists of three WLCSP MMICs, which are Tripler, an image-rejection DownConverter, and an LNA. Each MMIC was designed to operate for the full band [2]. Each WLCSP MMIC is SMT compatible because, as illustrated in previous literatures [2, 3], the circuitry is formed in a three-dimensional structure, which is covered with a ground metal except the pad areas, where employed transmission lines are inverted TFMS line.
Abstract—Newly developed E-band receiver (RX) and transmitter (TX) modules are demonstrated. The reflowsoldering compatibility of the 3-D WLCSP MMIC is made to assemble easily on PCB, which contributes to high mass productivity. The RX module is the first edition, and the TX module is the second edition with an improved Power Amplifier (PA). The PA is designed separately for lower and higher bands; 71 to 76 GHz and 81 to 86 GHz. For the TXs and RXs, the same Tripler and Mixer are employed, both of which perform at full band operation. The RX performances were measured with a conversion gain of 12 ± 1.5 dB and a noise figure of 5.5 ± 0.5 dB. The TX performances were measured with a conversion gain of 29 dB and a saturated output power level of 21 dBm. The WLCSP MMIC technology also provides simple reflow-soldering assembly and cost-effective production.
TX Tripler LO
Keywords—WLCSP; E-band; RX ; TX 16 x 12 mm2
I.
INTRODUCTION
II.
10 x 10
mm2
RF
65GHz to 92GHz
IF IF
Down Converter
71GHz to 76GHz 81GHz to 86GHz
Low Noise Amplifier RF
x3 21.6GHz to 30.7GHz
65GHz to 92GHz
71GHz to 76GHz 81GHz to 86GHz IF(I) IF(Q)
Fig.1. Photograph of TX and RX modules and corresponding block diagrams.
III.
DESIGN AND ON-WAFER EVALUATION OF LNA AND PA
The design of LNA is shown in Fig. 2. The LNA is constructed with a three-stage current-reuse HEMT (TripleHEMT) amplifier and a second two-stage current-reuse HEMT (Dual-HEMT) amplifier [2, 4]. Each gate width is 40 µm x 4. This topology is very effective to achieve high gain operation and die size shrink. Dual- and Triple-HEMT structures are frequently used in this chip set development. Furthermore, each HEMT was improved in the microstructures to minimize the parasitic capacitances. The noise matching was performed carefully in consideration of the loss of the inverse TFMS line stub. On-wafer measurement results are shown in Fig.3, where the gain and NF
RX AND TX CONSTRUCTION
First of all, the second edition of the E-band TX module and the first edition of the E-band RX module are shown in Fig. 1. The TX module consists of five WLCSP MMICs, which are a Tripler, a balanced Up-Converter, a single PA for driver amplifier, and a pair of PAs. The PA pairs are made
978-2-87487-032-3 © 2013 EuMA
Tripler LO
Power Amplifier x2
x3
21.6GHz to 30.7GHz
RX
Recently, E-band wireless communication systems are expected to be newly used in fixed networks for fiber extension or 3G/4G, LTE, and mobile backhaul, to support the extreme increase in Internet data transmission [1]. The frequency bands are allocated between 71 to 76 GHz and 81 to 86 GHz. Furthermore, the local frequency range is as wide as between 65 GHz and 92 GHz. We have demonstrated an E-band 3-D WLCSP chip set [2, 3] in the EuMWs; x3 frequency multiplier, ultra-wide-band amplifiers, balanced and image-rejection mixers, and Power Amplifiers. A TX module [3] with flip-chip mounted dies on the PCB indicated a potential for low cost production. In this paper, we will describe a newly designed Low Noise Amplifier (LNA) and an improved PA, and furthermore, describe an RX module and TX modules for both bands.
Power Up Converter Amplifier
588
6 -8 Oct 2013, Nuremberg, Germany
performances are shown for both the first amplifier and the LNA. The gain of the first amplifier was15 dB and the NF was 4.6 dB from 71 - 86 GHz. The gain of the LNA was 24 dB and the NF was 4.8 dB from 71 - 86 GHz. The NF performance of the LNA is dominated from the first amplifier characteristic. The LNA dissipates 40 mA at 6 V supply.
Amp
Amp Amp
Amp
Amp
Amp
Amp
Amp
2.9 x 2.3 mm2
AMP1
AMP2
RF out
RF in
VD
RF out RF in
VG
0.6 x 0.5 mm2
Pout [dBm], Gain[dB]
RF in
VD
Fig.2. Circuit configuration of designed LNA. The 1st Triple-HEMT amplifier is shown in detail.
40
71GHz 76GHz
15
30 Pout
10
20 Gain
5
10
35
NF [dB]
15
5 0
0 60
65
70
75 80 85 Frequency [GHz]
90
5
10
0
15
0 0
5 10 Pin [dBm]
15
A PA MMIC was flip-chip assembled on a designed PCB. The measurement reference line is shown with dotted lines. The die size is 2.9 x 2.3 mm2. This exhibited a saturated output power level at nearly 19 dBm, and a linear gain of 15 ~ 22 dB as shown in Fig. 6. The PA power consumption is 2.5W, respectively. Some improvements are going on now on the inter-stage design.
10
NF
5 10 Pin [dBm]
20
Gain
25
15 5
10
Fig.5. Measured response of the PA unit amplifier (on-wafer measurement).
20
Gain
10
30 Pout
30
Gain [dB]
Solid Line : 1st amplifier Dotted Line : LNA
15
Drain Efficiency
0 0
40
81GHz 86GHz
Drain Efficiency
0
20
20
Drain Efficiency[%]
20
RF out
Pout [dBm], Gain[dB]
2.3 x 1.1 mm2
Drain Efficiency[%]
0.8 x 0.5 mm2
Fig.4. The circuit scheme and photograph of the PA unit amplifier. The PA MMIC block diagram and the photograph are also shown to indicate the locations. The dotted lines in the amplifier scheme indicate the bias current flow.
95
Fig.3.Measured frequency response of the LNA (On-wafer measurement). RF out
RF in
The power amplifier was redesigned separately for lower and higher bands to increase the gain and the saturated output power level. The HEMT cell gate width has been increased to 50 µm x 6. Performance degradation of the cell is caused as the finger number increases. It is considerable, especially in the E-band. The microstructure improved for the LNA was extensively incorporated for better ft. The PA is a four-stage amplifier and the final stage has parallel-combined four unit amplifiers [3]. The circuit configuration of the improved unit amplifier and the on-wafer evaluation results are shown in Fig. 4 and Fig. 5, respectively. The gain vs frequency response is reasonably flat. The gain and saturated output power level was 7 dB and 17 dBm, respectively, and the maximum drain efficiency was 17 %. This amplifier dissipates 50 mA at 6 V supply.
DC Bias 30 Gain
Gain
20
20
Pout [dBm], Gain[dB], IM3[dBc]
Pout [dBm], Gain[dB], IM3[dBc]
30
10 Pout
0 -10 IM3
-20 -30
71GHz 76GHz
-40 -10
-5 0 Pin [dBm]
10
Pout
0 -10 IM3
-20 -30
81GHz 86GHz
-40
5
-10
Fig.6. Measured performance of a PA MMIC.
589
-5 0 Pin [dBm]
5
IV.
TX AND RX MODULES
All the 3-D WLCSP MMICs developed for the E-band applications were applied to construct RX and TX modules. Though there are some issues to be solved, such as better pad configuration to minimize the parasitic effects in the E-band, on-chip power combining efficiency, and so on, the modules exhibited reasonably good performance as shown in Fig. 6, 7, and 8. A fabricated RX module and its performances are shown in Fig. 7. The output IF signals are combined with an external IF quadrature coupler. The size of the PCB is merely 10 x 10 mm2. The measured conversion gain and NF were 12 ± 1.5 dB and 5.5 ± 0.5 dB, respectively. An undesired gain drop is observed near 86 GHz. It is the influence of the gain characteristic of the LNA. The total power consumption is 0.9 W. IF out
10
Desired 0
Gc [dB]
-10
Image fIF=1~15GHz fLO=30.354GHz PLO=10dBm x3fLO=91.062GHz PRF=-20dBm
-20 -30 -40 70
80
90 fRF [GHz]
50Ω
A fabricated TX module and its performance are shown in Fig. 9. A couple of PA MMICs are symmetrically combined on the PCB. The size of the PCB is merely 16 x 12 mm2. The saturated output power level was 21 dBm, which is 2 dB higher than that of the single PA MMIC on PCB. The linear gain was nearly 25 dB for the lower band and nearly 29 dB for the higher band. The IM3 level was -40 dBc at an IF input power level of around -18 dBm. The total power consumption is 8 W.
IF(Q) IF(I)
LO
RF
Tripler
D/C
110
Fig.8. Measured image-rejection characteristic of the RX module.
Ideal External 90˚ coupler 0°
90°
100
LNA
10 x 10 mm2 PA
LO
20
Tripler
fIF=1GHz fLO=22.004~30.354GHz PLO=10dBm
U/C
PA
RF
PA
Gc 16 x 12 mm2
10 IF IF
NF
40
5 PRFout [dBm], Gc[dB], IM3[dBc]
30
0 60
65
70
75 80 Frequency [GHz]
85
90
95
Fig.7. Measured RX performance on conversion gain and noise figuer. The PCB assembly is shown above the performance figure.
20 10
PRFout
0 -10 IM3
-20
fIF=20/15GHz PLO=10dBm fLO=30.354GHz
-30 -40
The image-rejection characteristic of the RX module is shown in Fig. 8, where the LO frequency is fixed at 30.354 GHz and the IF frequency is swept. The IR ratio is achieved at 25 dB or more.
40
71GHz 76GHz
Gc
PRFout [dBm], Gc[dB], IM3[dBc]
NF [dB], Gc [dB]
15
(Symmetry)
-20
-15
-10 -5 PIFin [dBm]
0
20 10
PRFout
0
IM3
-10 -20 fIF=10/5GHz PLO=10dBm fLO=30.354GHz
-30 -40
5
-20
Fig.9. Measured performances of a TX module.
590
81GHz 86GHz
Gc
30
-15
-10 -5 PIFin [dBm]
0
5
V.
REFERENCES
CONCLUSIONS
Newly developed E-band RX and TX modules are demonstrated. All the 3-D WLCSP MMICs developed for Eband application were applied to construct RX and TX modules. The fabricated RX module conversion gain and NF were 12 ± 1.5 dB and 5.5 ± 0.5 dB, respectively. The size of the PCB is merely 10 x 10 mm2. The fabricated TX module saturated output power level was 21 dBm. The linear gain was nearly 25 dB for the lower band and nearly 29 dB for the higher band. The IM3 level was -40 dBc at an IF input power level of around -18 dBm. The size of the PCB is merely 16 x 12 mm2. The WLCSP MMIC technology also provides simple reflowsoldering assembly and cost-effective production.
[1]
[2]
[3]
[4]
ACKNOWLEDGMENT The authors wish to acknowledge the assistance and support of the wafer process engineers.
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M. Piloni, G. Montiron, and A. G. Milani, “E-band microwave transceiver using MWgSP technology for PtP radio equipment,” in Proc. Of the 40th European Microwave Conference, Paris, Sept. 2010, pp. 2830. K. Tsukashima, M. Kubota, A. Yonamine, T. Tokumitsu, and Y. Hasegawa, “E-band radio link communication chipset in cost effective wafer level chip size package (WLCSP) technology,” in Proc. Of the 6th European Microwave Integrated Circuits Conference, Manchester, pp. 29-32, Oct. 2011. K. Tsukashima, M. Kubota, A. Yonamine, T. Tokumitsu, and Y. Hasegawa, “An E-Band Transmitter Module Constructed With Four WLCSP MMICs Solder-Reflowed On PCB,” in Proc. Of the 7th European Microwave Integrated Circuits Conference, Amsterdam, pp. 207-209, Oct. 2012. T. Tokumitsu, B. Piernas, A. Oya. K. Sakai, and Y. Hasegawa, “K-band 3-D MMIC low noise amplifier and mixer using TFMS lines with ground slit,” IEEE Microwave and Wireless Components Letters, vol. 15, no. 5, May 2005, pp. 318-320.