Switchless Matching Networks for Dual-Band Class-E Power Amplifiers - PowerPoint PPT Presentation

Switchless Matching Networks for Dual-Band Class-E Power Amplifiers Yifei Li, Zhen Zhang and Nathan M. Neihart Iowa State University MWSCAS 2014-College Station, TX.

Outline  Motivations  Dual-Band Matching Networks for Power Amplifiers  Proposed Dual-Band Matching Networks for Class E PA  Simulation Results  Conclusion 2/22

Motivations  Multi- band radio is a basic requirement for today’s wireless devices  Non-contiguous Carrier Aggregation requires concurrent operation  Simultaneous tasks Carrier 20 MHz #5 Carrier 20 MHz #4 Aggregated 100 MHz Mobile Data 20 MHz Carrier Capacity #1 Pipe Carrier 20 MHz #2 Carrier 20 MHz #3 3/22

Motivation for Dual-Band/Multi-Band Power Amplifier  PA is a major part of RF front end  Multi-band PA brings  Smaller area  Lower cost IPhone 5 mother board GSM Tx PA GSM Tx Primary Antenna WCDMA Tx PA WCDMA Tx Antenna Switch Typical PA module 4/22

Outline  Motivations  Dual-Band Output Matching Networks for Power Amplifiers  Switch-Based  Transmission-Line Based  Lumped Element Based  Proposed Dual-Band Matching Networks for Class E PA  Simulation Results  Conclusion 5/22

Single and Dual-Band Output Matching Networks  Output matching networks 50 Ω 50 Ω converts 50 Ω antenna load to desired load impedance Z Load Z Load (Z Load ) seen by the transistor  Usually low impedance  Single-band OMN: conversion only achieved at one frequency  Dual-band OMN: conversion can be achieved at two frequencies  We care about:  desired impedance  loss 6/22

Switch-Based Output Matching Networks  Disadvantages  Extra cost of RF switches  Extra loss of RF switches  Does not support concurrent operation  Advantages  Simple design  Can be extended to multiple bands 50 Ω Z Load 7/22 Luca Larcher et al, Design, Automation & Test in Europe Conference & Exhibition, Apr. 2009, pp.364-368.

Transmission Line and Lumped Element Output Matching Networks  Transmission line OMN  Disadvantages: Large area  Advantages: Low loss  Lump element OMN  Advantages: Small area.  Disadvantages: Circuit complexity an loss increase with number of supported frequency bands (beyond 3 bands)  This particular lumped element OMN has no control on harmonics V DD V DD λ /4 @ 3f 1 λ /4 @ 3f 2 50 Ω 50 Ω Z Load λ /4 @ 2f 1 λ /4 @ 3f 2 λ /2 @ 2f 2 Z Load Danish Kalim et al, IEEE International Microwave Symposium Digest(MTT), Jun. 2011, PP.1-4. 8/22 Koji Uchida et al, IEEE Asian-Pacific Microwave Conference Proceedings, Dec.2005.

Outline  Motivations  Dual-Band Matching Networks for Power Amplifiers  Proposed Dual-Band Output Matching Networks for Class E PA  All Lumped Element Output Matching Network  Transformer-Based Output Matching Network  Simulation Results  Conclusion 9/22

Conventional Single-Band Output Matching Network for Class E PA  Desired Z Load =7+j8 Ω at the design frequency, and high absolute impedance at harmonics  Part A realizes real-to-real impedance conversion, providing real part of desired impedance, R L , at design frequency  Part B provides X L at the design frequency and high impedance at harmonics L x L o C o C s B A L p 50 Ω Z Load =jX L +R L R L 10/22

Proposed Dual-Band Output Matching Networks for Class E PA  Desired impedance: 7+j8 Ω @ 800MHz and 1900MHz  Proposed all-lumped element output matching network C O L 1 L 2 L S C S 50 Ω B L P C 2 A C P Z Load =jX L +R L R L  Proposed transformer-based output matching network L S L 1 C O C S k L P L 2 C P 50 Ω Z eff A B C 2 R L Z Load =jX L +R L 11/22

All-Lumped Element Dual-Band OMN C O L 1 L 2  First consider the real-to-real L S C S 50 Ω impedance conversion B L P C 2 A C P  Part A converts 50 Ω to 7 Ω at both Z Load =jX L +R L R L frequencies  C sL , L pL form equivalent low-band L match L S C S 50 Ω  C sH , L pH form equivalent high-band C P L P L match R L  Component values in equivalent Low Band High Band single-band MNs can be C sL L sH calculated at each 50 Ω 50 Ω L pL C pH frequency R L,Low R L,High 12/22

All-Lumped Element Dual-Band OMN  Now consider the positive reactance  Part B provides +j8 Ω at both frequencies and high impedance at their harmonics C O L 1 L 2  Green box acts as a variable inductor L S C S 50 Ω B L P C 2 A C P Z Load =jX L +R L R L High band Low band L xL L xH L oH C o L oL C o  How to determine C O  Trade off between harmonic impedance (loss in power transistor) and loss in the matching network 13/22

Transformer-Based Dual-Band OMN  Part B provides +j8 Ω at both frequencies, and high impedance at their harmonics  Green box acts as a variable inductor  Red part of the expression is what we used  The rest is parasitic resistance C O L 1 L S C S 𝑙2𝑏 𝑙 2 1−𝑏 2 k L P 𝑅 50 Ω L 2 C P 𝑎 𝑓𝑔𝑔 = 𝜕𝑀 1 + 𝑘𝜕𝑀 1 1 + 2 2 1 + 1 1 + 1 Z eff A 𝑏 −𝑏 𝑏 −𝑏 𝑅2 𝑅2 B C 2 where R L Z Load =jX L +R L 𝜕 𝑝 = 1/ 𝑀 2 𝐷 2 , High band Low band 𝑅 = 𝜕 𝑝 𝑀 2 , 𝑆 2 L xH L oH C o L xL L oL C o 𝑏 (𝑀,𝐼) = 𝜕 (𝑀,𝐼) /𝜕 𝑝 14/22

Loss Optimization of Transformer-Based OMN C O  Sweep 𝜕 𝑝 , for each 𝜕 𝑝 , the values L 1 L S C S k L P 50 Ω L 2 C P of 𝑀 1 and 𝑙 can be determined. Z eff A B C 2 𝑙 2 1−𝑏 2 R L Z Load =jX L +R L 𝑀 1 1 + = 𝜕 𝑀 (𝑀 𝑌𝑀 +𝑀 𝑃𝑀 ) 2 1 + 1 High band 𝑏 −𝑏 𝑅2 Low band 𝑙 2 1−𝑏 2 𝑀 1 1 + = 𝜕 𝐼 (𝑀 𝑌𝐼 +𝑀 𝑃𝐼 ) 2 1 + 1 𝑏 −𝑏 𝑅2 L xH L xL L oH C o L oL C o  Loss model  Total loss in terms of parasitic resistance is expressed as 𝑙 2 𝑏 + 𝜕𝑀 1 𝑅 𝑅 𝑦 is the quality factor of 𝑄𝑏𝑠𝑏𝑡𝑗𝑢𝑗𝑑 𝑆𝑓𝑡 Ω = 𝜕𝑀 1 2 𝑅 𝑦 1 + 1 𝑀 1 at each frequency 𝑏 − 𝑏 𝑅 2  Parasitic resistance from the primary winding  Reflected parasitic resistance from the secondary winding 15/22

Loss Optimization of Transformer-Based OMN  Trade off between OMN loss and transistor loss  Higher harmonic impedance -> low loss in transistor  To increase the impedance at the 2 nd harmonic of low band, 𝝏 𝟏 should be closer to 𝟑𝒈 𝑴 .  𝜕 𝑝 is set at 2 π *1.25G rad/s  Higher loss in high band OMN  Higher loss in low band power transistor Parasitic Res H [ Ω ] Parasitic Res L [ Ω ] 16/22 Resonant frequency [GHz] Resonant frequency [GHz]

Outline  Motivations  Dual-Band Matching Networks for Power Amplifiers  Proposed Dual-Band Matching Networks for Class E PA  Simulation Results  Conclusion 17/22

Simulation Results  Simulation environment  HBT power transistor with 3.5V power supply  TDK MHG0603 (mm) inductors  Murata GJM 0603 (mm) capacitor  Low DC resistance (m Ω ) 1 μ H choke Inductor  Operation frequencies: 800MHz and 1900MHz  Substrate: 2-layer PCB with a thickness of 864 μ m, average dielectric constant of 3.57, metal thickness of 18 μ m, average loss tangent of 0.0036 V DD  Component values Choke Ind L S (nH) C S (pF) L P (nH) C P (pF) OMN 2.5 6.6 2.3 7.2 50 Ω L 1 (nH) L 2 (nH) C 2 (pF) C 3 (pF) k All-lumped 7 3.7 3.5 3.6 – Transformer 8.1 4 4.1 4.5 0.64 18/22 -based

Simulation Results  All-lumped output matching network  At 800MHz, η =71%@30.2dBm  At 1.9GHz, η =68%@29dBm  Transformer-based output matching network  At 800MHz, η =75%@30.1dBm  At 1.9GHz, η =67%@27.4dBm Transformer based 19/22 All-lumped element

Simulated Performance Comparison Simulated output Frequency Band Simulated Efficiency Ref Power* Load Type (GHz) (%) (watt/V 2 ) Switch- [2] 0.9/1.8 0.011 η=44/40 based/off chip 1.9/2.3/ η=64/62 [3] 0.02 On-chip 2.6/3.5 /59/58 η=73.6/ [4] 1.81/2.65 0.0075 TLs 70.1 PAE=51.6/ Lumped/ [6]** 0.8/1.5 0.05/0.026 51.9 Off chip This work all- lump load 0.8/1.9 0.067/0.038 η=75/67 Lumped/ network Off chip This work transformer 0.8/1.9 0.038 η=71/68 Lumped/ based Off chip * Output power normalized to V 2 DD ** Measured Result Luca Larcher et al, Design, Automation & Test in Europe Conference & Exhibition, Apr. 2009, pp.364-368. Ki Young Kim et al, IEEE Microwave and Wireless Components Letters, vol.21, no.7, July.2011. Danish Kalim et al, IEEE International Microwave Symposium Digest (MTT), Jun. 2011, pp.1-4. 20/22 Koji Uchida et al, IEEE Asian-Pacific Microwave Conference Proceedings, Dec.2005.

Conclusion  Two compact switchless dual-band output matching networks are designed for class E power amplifier which achieve drain efficiency above 67%, with transformer-based one having a little higher efficiency.  All-lumped element OMN is preferred when area is the main concern. Transformer could be several times larger than a lumped component.  Transformer-based OMN is preferred when performance is the main concern. Especially with advanced substrate and thick metal. In such circumstances, transformer based PA will have higher efficiency than all-lumped element PA. 21/22

Questions 22/22