Wideband 500W Power Amplier for UHF

Detalhes bibliográficos
Autor(a) principal: Monteiro, Micael Moreira
Data de Publicação: 2019
Tipo de documento: Dissertação
Idioma: eng
Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
Texto Completo: http://hdl.handle.net/10773/29718
Resumo: Until nowadays there never was a necessity of being constantly connected in the history of mankind. This necessity is the moving force behind the development of new wireless technologies capable of accommodating society’s necessities. Consequently, telecommunications systems which operate in different frequency bands exist and lead to increasing demands in terms of performance and cost. Power amplifiers are one of the most costly components in a RF front-end, specially in high power transmitters, telecommunications operators are continuously searching to implement devices which operate more efficiently and capable of operating in multiple frequency bands. Efficient amplifiers consume less energy and, therefore, less cooling equipment is required. Thus, the overall cost of the transmistter will be lowered. Wideband amplifiers handle multiple bands; this leads to less devices and lower maintenance costs. In the scope of work, a wideband class AB amplifier was implemented by using λ/4 coaxial cables baluns as power splitters/combiners in ADS (Advanced Design System). Two topologies of matching networks were studied and simulated. The first topology consists in multi-section quarter wave transformers. The second topology studied is made of lines and shunt capacitors. For both versions, the simulations show the gain is equal or greater to 20 dB and has less than a 1 dB of ripple for 470-740 MHz frequency band. The efficiency values assume to be in the order of 30-61% for input power in range of 30-39 dBm. Considering the 1-dB compression point, it varies between 57.5 dBm and 58.8 dBm for 470-740 MHz frequency band in the case where multi-section quarter wave lines were used as output matching networks. For the case where the output matching networks consist in lines with shunt capacitors, the 1-dB compression point varies between 57 dBm and 58.5 dBm for the same frequency band. After evaluating the performance and cost, the version which uses capacitors and lines was chosen. Thus, a two-tone signal with a spacing of 1kHz between carriers was fed to the amplifier and for a inter-modulation to carrier ratio of -30 dBc a power of 52.5 dBm per tone was obtained. Lastly, the layout was implemented and Eletromagnetic simulations were carried out for a more accurate model. The same simulations were repeated and the noted values are comparable to previously obtained results. After the amplifiers implementation, the gain was measured in a network analyzer and it showed that the gain is equal or greater than 20 dB for the 400-550 MHz frequency band. For the 550-630 MHz frequency band the amplifier has a gain that varies between 20 dB and 5 dB.
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spelling Wideband 500W Power Amplier for UHFBroadband amplifiersHigh power amplifiersTV broadcastingUHF devicesUntil nowadays there never was a necessity of being constantly connected in the history of mankind. This necessity is the moving force behind the development of new wireless technologies capable of accommodating society’s necessities. Consequently, telecommunications systems which operate in different frequency bands exist and lead to increasing demands in terms of performance and cost. Power amplifiers are one of the most costly components in a RF front-end, specially in high power transmitters, telecommunications operators are continuously searching to implement devices which operate more efficiently and capable of operating in multiple frequency bands. Efficient amplifiers consume less energy and, therefore, less cooling equipment is required. Thus, the overall cost of the transmistter will be lowered. Wideband amplifiers handle multiple bands; this leads to less devices and lower maintenance costs. In the scope of work, a wideband class AB amplifier was implemented by using λ/4 coaxial cables baluns as power splitters/combiners in ADS (Advanced Design System). Two topologies of matching networks were studied and simulated. The first topology consists in multi-section quarter wave transformers. The second topology studied is made of lines and shunt capacitors. For both versions, the simulations show the gain is equal or greater to 20 dB and has less than a 1 dB of ripple for 470-740 MHz frequency band. The efficiency values assume to be in the order of 30-61% for input power in range of 30-39 dBm. Considering the 1-dB compression point, it varies between 57.5 dBm and 58.8 dBm for 470-740 MHz frequency band in the case where multi-section quarter wave lines were used as output matching networks. For the case where the output matching networks consist in lines with shunt capacitors, the 1-dB compression point varies between 57 dBm and 58.5 dBm for the same frequency band. After evaluating the performance and cost, the version which uses capacitors and lines was chosen. Thus, a two-tone signal with a spacing of 1kHz between carriers was fed to the amplifier and for a inter-modulation to carrier ratio of -30 dBc a power of 52.5 dBm per tone was obtained. Lastly, the layout was implemented and Eletromagnetic simulations were carried out for a more accurate model. The same simulations were repeated and the noted values are comparable to previously obtained results. After the amplifiers implementation, the gain was measured in a network analyzer and it showed that the gain is equal or greater than 20 dB for the 400-550 MHz frequency band. For the 550-630 MHz frequency band the amplifier has a gain that varies between 20 dB and 5 dB.Até aos dias de hoje nunca houve uma necessidade tão grande de estar constantemente ligado às redes de informação. Esta necessidade é a força por trás do desenvolvimento de novas tecnologias sem-fios capazes de acomodar as necessidades da sociedade. Consequentemente, existem diversos sistemas de telecomunicações que cobrem múltiplas bandas de frequência o que leva a que o design de circuitos front-end para sistemas rádio seja cada vez mais exigente tanto em termos de desempenho como de custo. Sendo os amplificadores um dos elementos mais dispendiosos, procura-se, especialmente em emissores de alta potência, implementar dispositivos mais eficientes e que sejam capazes de cobrir o maior número de bandas de frequência possível. Dispositivos mais eficientes levam a menor energia dissipada e, portanto, menor necessidade de arrefecimento o que conduz a um menor custo do emissor. Amplificadores de banda larga permitem cobrir um maior número de bandas de frequência, levando a um menor número de dispositivos e por conseguinte a menores custos de manutenção. No âmbito deste trabalho foi realizado o projeto de um amplificador de banda larga, mais especificamente, um classe AB com baluns construídos com cabos coaxiais de λ/4 recorrendo ao software ADS (Advanced Design System). Foram abordadas duas topologias de malhas de adaptação e portanto foram estudadas duas versões. Uma versão em que a malha de adaptação da saída consiste em múltiplas secções de transformadores de λ/4 e outra em que essa malha de adaptação da saída foi implementada com linhas e condensadores em paralelo. Para ambos os casos, as simulações efetuadas revelam que o ganho ´e igual ou superior a 20 dB tendo menos do que 1-dB de ripple para a banda de frequência dos 470-740 MHz em que a eficiência assume valores entre os 30-61% para valores de potência de entrada na ordem dos 30-39 dBm. Relativamente à potência de saída no ponto de compressão de 1-dB, para a banda de frequência dos 470-740 MHz, esta varia entre os 57.5 dBm e os 58.8 dBm no caso em que a malha de adaptação da saída consiste em transformadores de λ/4. Para a variante em que a malha de adaptação da saída consiste em linhas e condensadores, o ponto de compressão de 1-dB varia entre os 57 dBm e 58.5 dBm para a mesma banda de frequência. Após avaliar o desempenho e custo de ambas as alternativas, optou-se por implementar a versão com linhas e condensadores e foram feitas simulações utilizando um sinal de duas portadoras com um espaçamento de 1kHz em que a distorção de intermodulação de -30 dBc corresponde a uma potência de 52.5 dBm por portadora. Por fim, realizou-se o layout e foi gerado um modelo eletromagnético que permitiu a realização das mesmas simulações, obtendo-se valores muito próximos dos obtidos previamente por simulação. Implementou-se o amplificador e obteve-se um ganho igual ou superior a 20 dB para a banda de frequência 400-550MHz. Para a banda dos 550-630 MHz o ganho assume valores entre os 20 dB e 5 dB.2020-11-05T10:04:34Z2019-12-01T00:00:00Z2019-12info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttp://hdl.handle.net/10773/29718engMonteiro, Micael Moreirainfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2024-02-22T11:57:30Zoai:ria.ua.pt:10773/29718Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T03:01:58.768442Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse
dc.title.none.fl_str_mv Wideband 500W Power Amplier for UHF
title Wideband 500W Power Amplier for UHF
spellingShingle Wideband 500W Power Amplier for UHF
Monteiro, Micael Moreira
Broadband amplifiers
High power amplifiers
TV broadcasting
UHF devices
title_short Wideband 500W Power Amplier for UHF
title_full Wideband 500W Power Amplier for UHF
title_fullStr Wideband 500W Power Amplier for UHF
title_full_unstemmed Wideband 500W Power Amplier for UHF
title_sort Wideband 500W Power Amplier for UHF
author Monteiro, Micael Moreira
author_facet Monteiro, Micael Moreira
author_role author
dc.contributor.author.fl_str_mv Monteiro, Micael Moreira
dc.subject.por.fl_str_mv Broadband amplifiers
High power amplifiers
TV broadcasting
UHF devices
topic Broadband amplifiers
High power amplifiers
TV broadcasting
UHF devices
description Until nowadays there never was a necessity of being constantly connected in the history of mankind. This necessity is the moving force behind the development of new wireless technologies capable of accommodating society’s necessities. Consequently, telecommunications systems which operate in different frequency bands exist and lead to increasing demands in terms of performance and cost. Power amplifiers are one of the most costly components in a RF front-end, specially in high power transmitters, telecommunications operators are continuously searching to implement devices which operate more efficiently and capable of operating in multiple frequency bands. Efficient amplifiers consume less energy and, therefore, less cooling equipment is required. Thus, the overall cost of the transmistter will be lowered. Wideband amplifiers handle multiple bands; this leads to less devices and lower maintenance costs. In the scope of work, a wideband class AB amplifier was implemented by using λ/4 coaxial cables baluns as power splitters/combiners in ADS (Advanced Design System). Two topologies of matching networks were studied and simulated. The first topology consists in multi-section quarter wave transformers. The second topology studied is made of lines and shunt capacitors. For both versions, the simulations show the gain is equal or greater to 20 dB and has less than a 1 dB of ripple for 470-740 MHz frequency band. The efficiency values assume to be in the order of 30-61% for input power in range of 30-39 dBm. Considering the 1-dB compression point, it varies between 57.5 dBm and 58.8 dBm for 470-740 MHz frequency band in the case where multi-section quarter wave lines were used as output matching networks. For the case where the output matching networks consist in lines with shunt capacitors, the 1-dB compression point varies between 57 dBm and 58.5 dBm for the same frequency band. After evaluating the performance and cost, the version which uses capacitors and lines was chosen. Thus, a two-tone signal with a spacing of 1kHz between carriers was fed to the amplifier and for a inter-modulation to carrier ratio of -30 dBc a power of 52.5 dBm per tone was obtained. Lastly, the layout was implemented and Eletromagnetic simulations were carried out for a more accurate model. The same simulations were repeated and the noted values are comparable to previously obtained results. After the amplifiers implementation, the gain was measured in a network analyzer and it showed that the gain is equal or greater than 20 dB for the 400-550 MHz frequency band. For the 550-630 MHz frequency band the amplifier has a gain that varies between 20 dB and 5 dB.
publishDate 2019
dc.date.none.fl_str_mv 2019-12-01T00:00:00Z
2019-12
2020-11-05T10:04:34Z
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