San Diego, CA Jan 09 CLASS E RF/MICROWAVE POWER AMPLIFIERS Class E broadband amplifier w ith C-LC shunt netw ork Basic theory, simulation and prototype A. Mediano 1 , K. Narendra 2 , C. Prakash 2 , 1 I3A, University of Zaragoza, Zaragoza, Spain 2 Motorola Technology, Penang, Malaysia RWW 2009 IEEE Topical Symposium on Pow er Amplifiers for Wireless Communications 2009 IEEE Topical Symposium on Power Amplifiers for Wireless Communications San Diego, CA Jan09 Motivation: Class E and broadband � Class E amps very interesting in modern communication systems … Large number of channels for a long period from a small-size battery. - Power amplifier is a main consumer of dc power from a battery. - Class E offers high operating efficiency near 100 % for ideal case. - � Class E amplifiers are narrowband by concept. Output network tuned to one frequency. - Nominal operation if switch “see” a nominal impedance at fo and harmonics. - Published results for broandband operation: Grebennikov, Raab, Al-Shahrani, - Gudimetla, Qin, Quach, Tat Hung, Tayrani, Everard, Pajic, etc. � Design of a broadband class E UHF amplifier ... With choke in drain to supply, - With C parallel with device (or more) included in output network - Load : 50 Ω Bandwidth : 403-470MHz Rated power : 4W Efficiency : 75% @ Pout= 5W Power supply : 7.5V Harmonic spectrum : Aditional filter for harmonic rejection. RWW 09 · A. Mediano · amediano@unizar.es 1
2009 IEEE Topical Symposium on Power Amplifiers for Wireless Communications San Diego, CA Jan09 Class E: basics of the idea Nominal switching ZLOAD RLOAD + jXLOAD @ fo VDC I DC = ∠ψ INFINITE @ nfo; n= 2,3,... Lchk XLOAD iR iSW ic vR RLOAD X= 0 @ fo vd Co X= ∝ @ nfo; n= 2,3,... Load network ZT Device Cout + Cext ∠ϕ Try a new output network designed to show almost ZLOAD for the complete broadband, 400-470MHz. RWW 09 · A. Mediano · amediano@unizar.es 2009 IEEE Topical Symposium on Power Amplifiers for Wireless Communications San Diego, CA Jan09 Broadband: output netw ork resonant to center of band Choke! ZB Virtual load ZA To avoid DC short and/or to add new To absorb too much Cout goals in design for Class E Analysis was done with similar RWW 09 · A. Mediano · amediano@unizar.es method as Raab’76. 2
2009 IEEE Topical Symposium on Power Amplifiers for Wireless Communications San Diego, CA Jan09 Broadband: equations for the design (1) Considering: i) the ZLOAD to show to device at fo; ii) the angle of ZLOAD to show to device (49º ); iii) the slope of that angle = 0 for broadband design; iv) the resonant frequency of LB-CB must be fo and v) the CA value must be a low impedance versus LA impedance. ⎡ ⎤ 1 ⎢ ⎥ ( ) 8.0 10 -4 2 ⎢ ⎥ ) 2 LBx ω x ψ x , , , , := tan ψ x + Cx tan ψ x ) + ... ( Cx Cdx Nratiox ) 175. ( 1 ( ⎢ ⎥ ω x 2 Cx 2 − 1 ( Nratiox 1. ) ⎢ ⎥ ( ) 2 ⎢ ⎥ ) 2 + tan ψ x + Cx Nratiox tan ψ x ) + ... 175. ( 1 ( ⎢ ⎥ ⎣ ) 2 ⎦ + + 98. Cdx Nratiox tan ψ x 98. Cdx Nratiox ( − Nratiox 1. 1250. Cx 2 CBx ω x ψ x , , , , := ( Cx Cdx Nratiox ) 1 ( ) 2 ) 2 tan ψ x + Cx tan ψ x ) + ... 175. ( 1 ( 1 ( ) 2 ) 2 + tan ψ x + Cx Nratiox tan ψ x ) + ... 175. ( 1 ( ) 2 + + 98. Cdx Nratiox tan ψ x 98. Cdx Nratiox ( Analysis was done with similar RWW 09 · A. Mediano · amediano@unizar.es method as Raab’76. 2009 IEEE Topical Symposium on Power Amplifiers for Wireless Communications San Diego, CA Jan09 Broadband: equations for the design (2) 1 ( ) 2 ) 2 tan ψ x + ( 1 LAx ω x ψ x , , , , := ( Cx Cdx Nratiox ) 7 Nratiox ω x 2 ⎡ ⎤ 25. tan ψ x − 25. tan ψ x + ... ( ) Nratiox Cx ( ) Cx ⎢ ⎥ 1 1 ⎢ ⎥ ( ) ( ) 2 2 ⎣ ) 2 ) 2 ⎦ + 7 Cdx Nratiox tan ψ x + − tan ψ x + ( 1 7. Cdx ( 1 1 ( ) 2 ) 2 tan ψ x + ( 1 Rx ω x ψ x , , , , := ( Cx Cdx Nratiox ) .28 Cx ω x ) 2 49. Cdx tan ψ x + + ... ( 49. Cdx 1 ( ) 2 ( ) ) 2 + tan ψ x + Cx tan ψ x 175. ( 1 ( ) 2 10 -2 Nratiox 2 10 -2 CAx ω x ψ x , , , , := − ( Cx Cdx Nratiox ) ) 2 tan ψ x + ( 1. Analysis was done with similar RWW 09 · A. Mediano · amediano@unizar.es method as Raab’76. 3
2009 IEEE Topical Symposium on Power Amplifiers for Wireless Communications San Diego, CA Jan09 The design: using the equations … Transistor RD07MVS1(Mitsubishi) : Nominal Ron= 0.18R Cout= 60pF From classical narrowband class E theory: Co = 16.8pF @ 403MHz, 15.5pF @ fo ; 14.4pF @ 470MHz Using equations: := ⋅ := ⋅ ψ x := ⋅ := ⋅ := ⋅ ψ x := ⋅ Cx 15.5 pF fx 436.5 MHz 49 deg Cx 15.5 pF fx 436.5 MHz 49 deg ω x := 2 π ⋅ ⋅ := ⋅ := ω x := 2 π ⋅ ⋅ := ⋅ := fx Cdx 45 pF Nratiox 10 fx Cdx 45 pF Nratiox 10 LBx ω x ψ x , , , , = ( Cx Cdx Nratiox ) 7.613 nH LB CB CBx ω x ψ x , , , , = 7.6 nH 17.5 pF ( Cx Cdx Nratiox ) 17.462 pF LAx ω x ψ x , , , , = ( Cx Cdx Nratiox ) 1.702 nH Rx ω x ψ x , , , , = 10.04 Ω LA ( Cx Cdx Nratiox ) 1.7 nH CAx ω x ψ x , , , , = Cd ( Cx Cdx Nratiox ) 781.007pF 45 pF , = + Ω ZLOAD fx Cx ( ) 4.321 4.971j CA , = 6.587 Ω 781 pF ZLOAD fx Cx ( ) RWW 09 · A. Mediano · amediano@unizar.es 2009 IEEE Topical Symposium on Power Amplifiers for Wireless Communications San Diego, CA Jan09 The design: output netw ork simulation 50 100 403.86 MHz 470.02 MHz |ZIN[1]| (L) 52.888 Deg 51.208 Deg Schematic 2 Ang(ZIN[1]) (R, Deg) 40 Schematic 2 50 436.52 MHz 30 49.108 Deg 436.5 MHz 0 6.5726 20 402.42 MHz 453.44 MHz 6.689 6.6488 -50 10 Frequency (MHz) 0 -100 300 600 900 RWW 09 · A. Mediano · amediano@unizar.es 4
2009 IEEE Topical Symposium on Power Amplifiers for Wireless Communications San Diego, CA Jan09 The design: block diagram Vdd Parallel capacitance of device (if bigger 7.5V that optimum value for desired Pout, the excess will be included in LOAD NET). FUNCTI ON: BI AS To help M1 in the L1 switching action CHOKE ZLOAD = RLOAD + jXLOAD = ZLOAD ∠ψ INPUT LOAD OUTPUT MATCH RL NETWORK DRV MATCH M1 50 Ω M1 LN M2 RF SOURCE 50 Ω 50 Ω Ro Ro FUNCTI ON: FUNCTI ONS: The matching FUNCTI ON: FUNCTI ON: 1) to show to device the nominal ZLOAD network is a broadband To generate drive To match 50ohm 2) to compensate the excess in Cdevice one with low pass signal for the input to input topology to match the 50 of our amplifier impedance of ohms load to the Ro device calculated value in previous stage. . RWW 09 · A. Mediano · amediano@unizar.es 2009 IEEE Topical Symposium on Power Amplifiers for Wireless Communications San Diego, CA Jan09 The design: matching driver About the input matching network M1 ... • ZIN = 1 Ω -j3 Ω @ 430MHz [123pF] • Broadband INPUT MATCH DRV M1 • Lowpass response. M1 • Maximum saturated gain in PA 50 Ω 50 Ω 50 Ω (1-j3) Ω L1 L2 L3 Topology ... 50ohms (1-j3) Ω C1 C2 RWW 09 · A. Mediano · amediano@unizar.es 5
2009 IEEE Topical Symposium on Power Amplifiers for Wireless Communications San Diego, CA Jan09 The design: output matching Simple (low parts count) and ladder L topology for broadband. Theoretical design ... L1 L2 L3 50ohms Ro =6-10 Ω C1 C2 C3 RWW 09 · A. Mediano · amediano@unizar.es 2009 IEEE Topical Symposium on Power Amplifiers for Wireless Communications San Diego, CA Jan09 The design: simulation (time domain) RWW 09 · A. Mediano · amediano@unizar.es 6
2009 IEEE Topical Symposium on Power Amplifiers for Wireless Communications San Diego, CA Jan09 Prototype: the driver Arturo Mediano Bias Measurement with E7402A Agilent Spectrum Analyzer with tracking generator set to 0dBm, VDD= 7.1V (IDD= 490mA), VGG= 3V. A 30dB (5W) attenuator is used in the setup and corrections are included on screen. RWW 09 · A. Mediano · amediano@unizar.es 2009 IEEE Topical Symposium on Power Amplifiers for Wireless Communications San Diego, CA Jan09 Prototype: the class E PCB OUTPUT MATCHING CHOKE INPUT MATCHING XTOR OUTPUT NETWORK RWW 09 · A. Mediano · amediano@unizar.es 7
2009 IEEE Topical Symposium on Power Amplifiers for Wireless Communications San Diego, CA Jan09 Prototype: characterization setup BI RD BI RD Rfout sensor Rfin sensor RFI N RFOUT From RF CLASS E To 50hm generator 0-5W AMPLI FI ER load driver through a 30dB att Arturo Mediano RWW 09 · A. Mediano · amediano@unizar.es 2009 IEEE Topical Symposium on Power Amplifiers for Wireless Communications San Diego, CA Jan09 Prototype: measurements 90% 5,0 81,8% 4,44 79,6% 4,5 80% 4,05 75,4% 3,70 4,0 70% 63,6% 3,5 Output power (W) 60% 3,46 Efficiency (%) 3,39 49,2% 47,9% 3,0 50% 2,5 40% 2,0 30% 1,5 1,66 Eff_drain (%) 20% 1,0 PAE (%) 10% 0,5 Pout (W) Frequency (MHZ) 0% 0,0 350 370 400 430 470 500 RWW 09 · A. Mediano · amediano@unizar.es 8
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