Momwe mungakwaniritsire ma impedance mafananidwe a ma waveguides?Kuchokera pa chiphunzitso cha mzere wopatsirana mu chiphunzitso cha microstrip antenna, tikudziwa kuti mizere yoyenera kapena mizere yolumikizirana yofananira imatha kusankhidwa kuti ikwaniritse zofananira zofananira pakati pa mizere yopatsira kapena pakati pa mizere yopatsira ndi katundu kuti akwaniritse kufalikira kwamphamvu komanso kutayika kocheperako.Mfundo yomweyo yofananira ndi impedance mu mizere ya microstrip imagwiranso ntchito pakufananitsa kwa impedance mu ma waveguides.Kuwonetsera mu machitidwe a waveguide kungayambitse kusagwirizana kwa impedance.Pamene kuwonongeka kwa impedance kumachitika, njira yothetsera vutoli ndi yofanana ndi mizere yopatsirana, ndiko kuti, kusintha mtengo wofunikira The lumped impedance imayikidwa pazigawo zowerengeka kale mu waveguide kuti athetse kusagwirizana, potero kuchotsa zotsatira zowonetsera.Ngakhale mizere yopatsira imagwiritsa ntchito zotchingira zopindika kapena ma stubs, ma waveguide amagwiritsa ntchito zitsulo zamitundu yosiyanasiyana.
chithunzi 1: Waveguide irises ndi dera lofanana, (a) Capacitive; (b) inductive; (c) resonant.
Chithunzi 1 chikuwonetsa mitundu yosiyanasiyana yofananira yofananira, kutenga mawonekedwe aliwonse omwe awonetsedwa ndipo amatha kukhala opatsa chidwi, ochititsa chidwi kapena owoneka bwino.Kusanthula masamu ndizovuta, koma kufotokoza kwakuthupi sikuli.Poganizira mzere woyamba wazitsulo wa capacitive pachithunzichi, zitha kuwoneka kuti kuthekera komwe kunalipo pakati pa makoma apamwamba ndi pansi a waveguide (munjira yayikulu) tsopano ilipo pakati pazigawo ziwiri zachitsulo moyandikana kwambiri, kotero mphamvu ndi The mfundo ikuwonjezeka.Mosiyana ndi izi, chipika chachitsulo chomwe chili mu Chithunzi 1b chimalola kuti pakali pano ikuyenda pamene sichinayambe kuyenda.Padzakhala kuyenda kwapano mu ndege yamagetsi yomwe idakonzedwa kale chifukwa chowonjezera chipika chachitsulo.Chifukwa chake, kusungirako mphamvu kumachitika m'maginito ndipo inductance pamalopo a waveguide imawonjezeka.Kuonjezera apo, ngati mawonekedwe ndi malo a mphete yachitsulo mu Chithunzi c apangidwa momveka bwino, kukhudzidwa kwa inductive ndi capacitive reactance kumayambitsa kudzakhala kofanana, ndipo kabowo kadzakhala kofanana.Izi zikutanthauza kuti kufananiza kofananira ndikusintha kwamayendedwe akulu ndikwabwino kwambiri, ndipo kuthamangitsidwa kwamtunduwu kumakhala kochepera.Komabe, mitundu ina kapena ma frequency adzachepetsedwa, kotero mphete yachitsulo yowoneka bwino imakhala ngati fyuluta ya bandpass ndi sefa ya mode.
chithunzi 2:(a) zolemba zawaveguide;(b)zowotchera ziwiri
Njira ina yoyimba ikuwonetsedwa pamwambapa, pomwe chitsulo cha cylindrical chimachokera ku mbali yayikulu kupita ku waveguide, kukhala ndi zotsatira zofananira ndi chingwe chachitsulo popereka kuyankha kwamphamvu panthawiyo.Chitsulo chachitsulo chikhoza kukhala capacitive kapena inductive, kutengera kutalika komwe kumafikira mu waveguide.Kwenikweni, njira yofananira iyi ndi yakuti pamene mzati wachitsulo woterewu ukukwera pang'ono mu waveguide, umapereka chidziwitso cha capacitive panthawiyo, ndipo kutengeka kwa capacitive kumawonjezeka mpaka kulowa mkati kuli pafupi kotala la kutalika kwa mawonekedwe, Panthawiyi, mndandanda wa resonance umapezeka. .Kulowa kwinanso kwachitsulo chachitsulo kumapangitsa kuti chiwopsezo cha inductive chikuperekedwa chomwe chimachepa pamene kuyika kumakhala kokwanira.Kuchulukira kwa resonance pakuyika kwapakati kumayenderana molingana ndi kukula kwa gawolo ndipo kumatha kugwiritsidwa ntchito ngati fyuluta, komabe, pakadali pano imagwiritsidwa ntchito ngati fyuluta yoyimitsa gulu kuti itumize mitundu yapamwamba.Poyerekeza ndi kuwonjezereka kwazitsulo zazitsulo, ubwino waukulu wogwiritsira ntchito zitsulo zachitsulo ndikuti ndizosavuta kusintha.Mwachitsanzo, zomangira ziwiri zitha kugwiritsidwa ntchito ngati zida zosinthira kuti zigwirizane bwino ndi ma waveguide.
Zoletsa zolemetsa ndi zochepetsera:
Monga njira ina iliyonse yopatsirana, ma waveguide nthawi zina amafunikira kufananiza koyenera komanso kuwongolera katundu kuti azitha kuyamwa mafunde obwera popanda kuwunikira komanso kusamva pafupipafupi.Ntchito imodzi yamaterminals ndi kupanga miyeso yosiyanasiyana yamagetsi padongosolo popanda kuwunikira mphamvu iliyonse.
chithunzi 3 kukana kwa ma waveguide (a) tepi imodzi (b) kapu iwiri
Kuthetsa kofala kwambiri ndi gawo la dielectric lotayika lomwe limayikidwa kumapeto kwa waveguide ndi tapered (ndi nsonga yolozera ku mafunde omwe akubwera) kuti asapangitse kuwunikira.Sing'anga yotayikayi imatha kukhala m'lifupi lonse la waveguide, kapena imatha kukhala pakatikati pa mapeto a waveguide, monga momwe tawonera pa Chithunzi 3. The taper ikhoza kukhala imodzi kapena iwiri taper ndipo nthawi zambiri imakhala ndi kutalika kwa λp/2, ndi utali wonse wa pafupifupi mafunde awiri.Nthawi zambiri amapangidwa ndi mbale za dielectric monga galasi, yokutidwa ndi filimu ya carbon kapena galasi lamadzi kunja.Pazogwiritsa ntchito mphamvu zambiri, ma terminals oterowo amatha kukhala ndi masinki otentha omwe amawonjezedwa kunja kwa ma waveguide, ndipo mphamvu yoperekedwa ku terminal imatha kutayidwa kudzera mu sinki yotentha kapena kuziziritsa mokakamizidwa.
chithunzi 4 Zosuntha vane attenuator
Ma dielectric attenuators amatha kuchotsedwa monga momwe tawonetsera pa Chithunzi 4. Ikayikidwa pakati pa waveguide, imatha kusunthidwa mozungulira kuchokera pakatikati pa waveguide, komwe ipereka chiwopsezo chachikulu, mpaka m'mphepete, komwe kuchepetsedwa kumachepetsedwa kwambiri. popeza mphamvu yakumunda yamagetsi yamachitidwe akuluakulu ndi otsika kwambiri.
Kuchepetsa mu waveguide:
Kuchepetsa mphamvu kwa ma waveguides makamaka kumaphatikizapo izi:
1. Zowunikira kuchokera ku ma waveguide discontinuities kapena magawo olakwika a waveguide
2. Kutayika komwe kumachitika chifukwa chakuyenda kwa makoma a waveguide
3. Kutayika kwa dielectric mumayendedwe odzaza mafunde
Ziwiri zomalizira ndizofanana ndi zotayika zofanana mu mizere ya coaxial ndipo zonse ndizochepa.Kutayika kumeneku kumadalira zinthu zapakhoma ndi roughness yake, dielectric ntchito ndi pafupipafupi (chifukwa cha zotsatira za khungu).Kwa ngalande yamkuwa, mitunduyi imachokera ku 4 dB / 100m pa 5 GHz mpaka 12 dB / 100m pa 10 GHz, koma panjira ya aluminiyamu, mawonekedwe ake ndi otsika.Kwa ma waveguide okhala ndi siliva, zotayika nthawi zambiri zimakhala 8dB/100m pa 35 GHz, 30dB/100m pa 70 GHz, ndipo pafupi ndi 500 dB/100m pa 200 GHz.Kuti muchepetse kutayika, makamaka pama frequency apamwamba kwambiri, ma waveguide nthawi zina amakutidwa (mkati) ndi golide kapena platinamu.
Monga tafotokozera kale, waveguide imagwira ntchito ngati fyuluta yapamwamba.Ngakhale ma waveguide pawokha ndiwopanda kutayika, ma frequency omwe ali pansi pa cutoff frequency amachepetsedwa kwambiri.Kuchepetsa uku kumachitika chifukwa chakuwunikira pakamwa pa waveguide osati kufalitsa.
Kuphatikiza kwa Waveguide:
Kulumikizana kwa Waveguide nthawi zambiri kumachitika kudzera mu flanges pamene zidutswa za waveguide kapena zigawo zake zimalumikizidwa palimodzi.Ntchito ya flange iyi ndi kuonetsetsa yosalala makina kugwirizana ndi oyenera katundu magetsi, makamaka otsika kunja cheza ndi otsika kusinkhasinkha mkati.
Flange:
Ma Waveguide flanges amagwiritsidwa ntchito kwambiri polumikizirana ndi ma microwave, makina a radar, kulumikizana kwa satellite, machitidwe a antenna, ndi zida za labotale pakufufuza kwasayansi.Amagwiritsidwa ntchito kulumikiza magawo osiyanasiyana a waveguide, kuwonetsetsa kuti kutayikira ndi kusokonezedwa kumapewedwa, ndikusunga kulondola kwa ma waveguide kuti zitsimikizire kufalikira kodalirika komanso kuyika bwino kwa mafunde a frequency electromagnetic.Ma waveguide wamba amakhala ndi flange kumapeto kulikonse, monga momwe tawonetsera pa Chithunzi 5.
chithunzi 5 (a) plain flange;(b)flange coupling.
Pamafupipafupi, flange imawungidwa kapena kuwotcherera ku ma waveguide, pomwe pama frequency apamwamba imagwiritsidwa ntchito.Zigawo ziwiri zikalumikizidwa, ma flange amangiriridwa palimodzi, koma malekezero ayenera kumalizidwa bwino kuti apewe kusokoneza kulumikizana.Mwachiwonekere ndikosavuta kugwirizanitsa zigawozo molondola ndi zosintha zina, kotero kuti mafunde ang'onoang'ono nthawi zina amakhala ndi ma flanges omwe amatha kulumikiza pamodzi ndi mtedza wa mphete.Pamene ma frequency akuchulukirachulukira, kukula kwa ma waveguide coupling kumachepa mwachibadwa, ndipo kusagwirizana kumakula molingana ndi kutalika kwa chizindikiro ndi kukula kwa waveguide.Chifukwa chake, ma discontinuities pama frequency apamwamba amakhala ovuta kwambiri.
chithunzi 6 (a)Chigawo chodutsa cholumikizira chokokera;(b)mawonedwe akumapeto a choko flange
Kuti athetse vutoli, kusiyana kochepa kungasiyidwe pakati pa ma waveguides, monga momwe tawonetsera pa Chithunzi 6. Kulumikizana kotsamwitsa komwe kumakhala ndi flange wamba ndi flange yotsamwitsa yolumikizidwa palimodzi.Kubwezera zomwe zingatheke, mphete yozungulira yozungulira yokhala ndi gawo lofanana ndi L imagwiritsidwa ntchito mu choke flange kuti agwirizane kwambiri.Mosiyana ndi ma flanges wamba, ma flanges amatsamwitsa pafupipafupi, koma mawonekedwe okhathamiritsa amatha kutsimikizira bandwidth yololera (mwina 10% yapakati pafupipafupi) pomwe SWR sipitilira 1.05.
Nthawi yotumiza: Jan-15-2024
