Concurrent Multiband Low Noise Amplifier With Multisection Impedance Transformer

Gunawan Wibisono1 and Teguh Firmansyah2

1Dept. of Electrical Engineering, University of Indonesia, Kampus Baru UI Depok, 16424, INDONESIA 2Dept of Electrical Engineering, University of Sultan Ageng Tirtayasa, Kampus Cilegon, INDONESIA

Abstract — In this paper, multiband low noise amplifier (LNA) with multi-section impedance transformer (MIT) as impedance matching is designed, fabricated and evaluated. MIT

is used as input and output impedance matching because MIT has higher stability, large Q factor, and low noise than lumped component. MIT is easy to fabricate and measure. The aim of

the research is to design multiband LNA with MIT at center frequencies located at 0.95 GHz for GSM, 1.85 GHz for WCDMA and 2.65 GHz for LTE. Designed and evaluated of the

proposed multiband LNA with MIT is done by using advanced desain system (ADS). It shown from the simulated results that performances of the proposed LNA at center frequency of 0.950

GHz has return loss, S11 = -23.541 dB, insertion loss, S21 = 18.911 dB, noise figure, NF = 1.475 dB, VSWR = 1.143, and FoM = 8.38, respectively. At center frequency of 1.85 GHz, the proposed LNA

has S11 = -23.771 dB, S21 = 12.858 dB, NF = 1.988 dB, VSWR = 1.139, and FoM = 2.616. At center frequency 2.65 GHz, the proposed LNA has S11 = -23.521 dB, S21 = 10.180 dB, NF = 2.776

dB, VSWR = 1.143, and FoM = 1.152. The center frequencies of fabricated proposed multiband LNA with MIT are shifted in average to 5-10 MHz lead to simulation results, and the

performances of the fabricated of the proposed LNA with MIT are degraded about 7-10% by using Monte-Carlo Yield Analysis.

Index Terms — Concurrent multiband LNA, multi-section impedance transformer (MIT).

I. INTRODUCTION

In order to realize the multi standard access in RF terminals, the main part in RF front end, low noise amplifier (LNA), must be designed to operate at two or more frequency bands (multiband). Multiband LNA is designed to achieve compact design and higher levels of integration for the reduction of costs and size [1]-[2], as well as had better performance in return loss, S11, insertion loss, S21, stability, K, and voltage standing wave ratio (VSWR) [3].

Wideband LNA as one type of multiband LNA has been designed to operate at some frequency bands with wide bandwidth, however this LNA amplify unused frequency which could increase interference [4]. Therefore, wideband LNA needs sharp filter to reduce the interferencies. In other case, multiband switching LAN has been designed to reduce interferences of wideband LNA, but this LNA can be maximum operated only at one given frequency at any time [5]. This LNA also need the switching which have small time delay to achieve good performance.

Concurrent multiband LNA has been proposed operate at some frequencies with good performances of S11, S21, NF, K,

and VSWR at those frequencies at the same time [6]-[8]. The implementation of concurrent multiband can be done by using lumped components as multiband resonators and as well as input and output matching impedances. However, the using of many lumped components can be increased the noise. Another method to design concurrent multiband LNA is by using multisection impendace transformer (MIT), which the MIT has many benefits including low noise, high stability, and easy in fabrication [9].

Concurrent multiband LNA with shunt-peaking and lumped components as multiband matching had been designed to operate at frequencies 2.4 GHz, 3.5GHz, and 5.2 GHz [6]. This LNA had performances of S21 = 11.79 dB, 11.70 dB, and 10.06 dB at 2.4 GHz, 3.5 GHz, and 5.2 GHz, respectively. NF performance of this LNA is 3.89 dB, 4.03 dB, and 3.73 dB at frequencies 2.4 GHz, 3.5 GHz, and 5.2 GHz, respectively. NF of this multiband LNA is still high because of large noise which caused by the using of transistor and inductor that used as multiband matching. Dualband LNA with impedance transformer as matching impedance had been designed and evaluated [7]. It is shown that dualband LNA had performances of S21 = 22 dB at 2.45 GHz, 12 dB at 5.2 GHz, and NF = 1,5 dB at 2.4 GHz, and 1.6 dB at 5.2 GHz [7]. It is shown that the LNA impedance transformer had NF that lower than LNA with lumped component. Multiband LNA with MIT based on CMOS technology had been designed and evaluated. The performances of multiband LNA with MIT based on CMOS are S21 = 22.4 dB at 2.4 GHz, 21.1 dB at 3.5 GHz, and 20,7 dB at 5.5 GHz; NF = 0,9 dB at 2.4 GHz, 1.2 dB at 3.5 GHz, and 1.3 dB at 5.2 GHz. It is shown that the multiband LNA with MIT had lower NF compare than that of LNA with lumped component. However, multiband LNA with MIT based on CMOS had high power consumption more than 40 mW and K at high frequency is not good.

In this research, concurrent multiband LNA with MIT as input and output impedance matching will be designed, fabricated, and evaluated. The proposed concurrent multiband LNA with MIT will be operated at center frequencies of 0.95, 1.85 and 2.65 GHz. The requirement performance parameters of the proposed concurrent multiband LNA with MIT are given by S11 < -10 dB, VSWR < 2, S21 > 10 dB and NF < 3 dB at all three frequencies. Design and performance evaluation are encouraged by using Advance Design System

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(ADS). The performances of designing concurrent multiband LNA with MIT are compared to the fabricated LNA performance results.

II. DESIGN OF MULTIBAND LNA WITH MIT

In designing concurrent multiband LNA, the first step is determining the LNA specifications which will be designed. The second is choosing the transistor and determining the DC bias of the transistor to know the LNA operation. The third step is determining input and output impedance, here is using MIT. Figure 1. shows the proposed concurrent multiband LNA with MIT as input and output impedance matching.

Figure 1. The proposed concurrent multi-band LNA with MIT At the input impedance matching by using MIT, the reflection

coefficients for three band frequencies are given by

(1)

The input impedance is given by (2)

where

and �

The width (W) and length (L) of the microstrip MIT can be found by using Quisi-Newton algorithm which proposed by [8]. The optimum size of W and L of the MIT are shown in Table 1.

Table 1. The Optimum Size of MIT

TL W (mm) L (mm) TL-1 4.3 20

TL-2 4.5 20 TL-3 20 20 TL-4 10.8 19.3 TL-5 2.3 20 TL-6 0.5 20

The proposed LNA is then fabricated using copper

metallization on the substrate FR4 with a relative dielectric constant of 4.3, a loss tangent of 0.002 and a thickness of 1.6 mm. The proposed LNA with MIT has been fabricated using copper metallization on the substrate FR4 with a relative dielectric constant of 4.3, a loss tangent of 0.002 and a thickness of 1.6 mm. The fabricated of the proposed multiband LNA is shown on Figure 2.

Figure 2. The fabricated of the proposed LNA with MIT

II. RESULTS

In this section, the simulation results of the concurrent multiband LNA with MIT which simulated by Agilent’s ADS and measured results are presented. Figure 3. (a)., (b)., (c)., and (d). show respectively the simulated and measured S11, S21, VSWR, and NF of the proposed LNA with MIT. It is shown from Figure 3. that the simulated and measured S11, S21, VSWR, and NF results are satisfied to designed requirements. However, compare to the simulated results, the center frequencies of the fabricated LNA are shifted, in average to 5 - 10 MHz lead to the simulated results. By using Monte-Carlo Yielded Analysis proposed at [8], the performances of the fabricated of the proposed LNA are degraded about 7-10% compared to the simulated results.

(a). (b). ( c). (d).

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Figure 3. The fabricated and simulated of the proposed LNA with MIT (a). S11 (b). S21 (c). VSWR (d). NF

Table 2. shows the comparison of figure of merit (FoM) of

the proposed multiband LNA with MIT compared to [7], [9]

and [10], where FoM is given by [11]

(3)

It is shown from Table 2. that the FoM of the proposed

LNA with MIT is higher than that of another multiband LNA.

VII. CONCLUSION

Concurrent multiband LNA with MIT that can be operated

simultaneously at center frequencies of 0.95, 1.85, and 2.65

GHz has been designed, fabricated, and analyzed. It is shown

from the simulated and fabricated results of S11, S21, VSWR,

and NF of the proposed concurrent multiband LNA with MIT

are satisfied to design requirements. However, the center

frequencies of fabricated proposed multiband LNA with MIT

are shifted, in average to 5-10 MHz lead to simulation results,

it is about 7-10% variation of the performance degradation by

using Monte-Carlo Yield Analysis. It is also shown that the

proposed multiband LNA had higher FoM compared to

another type of mutliband LNA.

ACKNOWLEDGEMENT

This research is supported by International Collaboration Research Grant from Directorate Research and Community Development (DRPM) University of Indonesia, 2012, No. 1165/H2.R12/HKP 05.00.Perjanjian/2012.

REFERENCES

[1]. David G. Rahn, Mark S. Cavin, "A Fully Integrated Multiband MIMO WLAN Transceiver RFIC," IEEE Journal Of Solid-State Circuit, Vol. 50, No.18. August 2005.

[2]. Jung. Kwangchun, “CMOS RFIC of Multiband Transceiver for Communication Systems” Ph.D. Dissertation. University of Florida. Florida. 2008.

[3]. Motoroiu. Serban, “Multiband/Multimode RF Front-End Receiver For Basestation Applications” M.S. Thesis. Delft University of Technology. Delft. Agustus 2011.

[4]. He, K.-H., M.-T. Li, C.-M. Li, and J.-H. Tarng, “Parallel- RC feedback low-noise amplifier for UWB applications,” IEEE Transactions on Circuits and Systems — II: Express Briefs, Vol. 57, No. 8, 582–586, 2010.

[5]. Tzeng, F., A. Jahanian, and P. Heydari, “A multiband inductor- reuse CMOS low-noise amplifier,” IEEE Transactions on Circuits and Systems — II: Express Briefs, Vol. 55, No. 3, 209–213, 2008.

[6]. Jhon, H.-S., I. Song, J. Jeon, H. Jung, M. Koo, B.-G. Park, J. D. Lee, and H. Shin, 8mW 1,7/2,4 GHz dual-band CMOS low-noise amplifier for ISM-band application," IEEE Electronics Letters,Vol. 44, No. 23, 1353-1354, Nov. 2008.

[7]. Erick Emmanuel, Ke Wu, “Dual-Band Low-Noise Amplifier Using Step Impedance Resonator (SIR) Technique for Wireless System Applications” Proceedings of the 39th European Microwave Conference. 29 September - 1 October 2009, Rome, Italy

[8]. Agilent Technologies. “Statistical Simulation (Monte Carlo and Yield ) in ADS”. ADS RF Circuit Design Cook Book vol. 1, ver. 1. 2008

[9]. Kargaran, E. and B. Madadi, “Design of a novel dual-band concurrent CMOS LNA with current reuse topology," Int. Conf. on Networking and Information Technology, 386-388, Jun. 2010.

[10]. Hsiao, C.-L. and Y.-L. Huang, ”A low supply voltage dualband low noise amplifier design,"13th IEEE Int. Symp. on Consumer Electronics, 339-341, May 2009.

[11]. Okazaki, H., K. Kawai, A. Fukuda, T. Furuta, and S. Narahashi, “Reconfigurable amplifier towards enhanced selectivity of future multi-band mobile terminals,” International Microwave Workshop Series on RF Front-ends for Software Defined and Cognitive Radio Solutions, 1–4, 2010.

Table 2. Performance Comparison of FoM of Multiband LNA

Parameters Reference

Proposed [7] [9] [10]

Type Concurrent Simultaneous

fc (GHz) 1,80 2,45 2,40 5,20 2,20 4,60 0,95 1,85 2.65

S21 (dB) 9,20 12,00 15,00 6,50 10,80 8,80 18,91 12,85 10,18

NF (dB) 5,70 6,40 2,50 2,40 3,53 2,52 1,45 1,98 2,76

PDC (mW) 8,00 10,00 7,76 4,97

FoM (mW-1) 0,38 0,59 4,07 0,61 1,21 1,24 8,30 2,61 1,15

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