Kodi tingakwaniritse bwanji kufanana kwa impedance kwa ma waveguides? Kuchokera ku chiphunzitso cha mzere wotumizira mu chiphunzitso cha microstrip antenna, tikudziwa kuti mizere yoyenera kapena yotumizira yofanana ingasankhidwe kuti ikwaniritse kufanana kwa impedance pakati pa mizere yotumizira kapena pakati pa mizere yotumizira ndi katundu kuti ikwaniritse kutumiza kwamphamvu kwambiri komanso kutayika kochepa kwa chiwonetsero. Mfundo yomweyi yofananira ya impedance mu mizere ya microstrip imagwiranso ntchito pa kufanana kwa impedance mu ma waveguides. Kuwunikira mu machitidwe a waveguide kungayambitse kusalingana kwa impedance. Pamene kuwonongeka kwa impedance kumachitika, yankho limakhala lofanana ndi la mizere yotumizira, ndiko kuti, kusintha mtengo wofunikira. Impedance yolumikizidwa imayikidwa pamalo owerengedwa kale mu waveguides kuti ithetse kusalingana, potero kuchotsa zotsatira za kuwunikira. Ngakhale mizere yotumizira imagwiritsa ntchito ma impedance olumikizidwa kapena stubs, ma waveguides amagwiritsa ntchito zitsulo zamitundu yosiyanasiyana.
chithunzi 1: Ma irises a Waveguide ndi dera lofanana,(a)Capacitive;(b)inductive;(c)resonant.
Chithunzi 1 chikuwonetsa mitundu yosiyanasiyana ya kufananiza kwa impedance, kutenga mawonekedwe aliwonse omwe awonetsedwa ndipo kungakhale kogwira mtima, koyambitsa kapena kogwirizana. Kusanthula kwa masamu ndi kovuta, koma kufotokozera kwenikweni sikokwanira. Poganizira mzere woyamba wachitsulo wothandiza mu chithunzicho, zitha kuwoneka kuti kuthekera komwe kunalipo pakati pa makoma apamwamba ndi pansi a waveguide (mu dominant mode) tsopano kuli pakati pa malo awiri achitsulo pafupi, kotero capacitance ndi The point ikuwonjezeka. Mosiyana ndi zimenezi, block yachitsulo mu Chithunzi 1b imalola kuti magetsi aziyenda komwe sikunayendepo kale. Padzakhala kuyenda kwamagetsi mumlengalenga wamagetsi womwe udakulitsidwa kale chifukwa cha kuwonjezera block yachitsulo. Chifukwa chake, kusungirako mphamvu kumachitika mu magnetic field ndipo inductance pamalo amenewo a waveguide ikuwonjezeka. Kuphatikiza apo, ngati mawonekedwe ndi malo a mphete yachitsulo mu Chithunzi c zapangidwa moyenera, reactance yothandiza ndi capacitive reaction yomwe yayambitsidwa idzakhala yofanana, ndipo kutsegula kudzakhala parallel resonance. Izi zikutanthauza kuti kufananiza ndi kusintha kwa impedance ya main mode ndikwabwino kwambiri, ndipo mphamvu ya shunting ya main mode sidzakhala yotsika. Komabe, ma mode ena kapena ma frequency adzachepetsedwa, kotero mphete yachitsulo yozungulira imagwira ntchito ngati fyuluta ya bandpass komanso fyuluta ya mode.
chithunzi 2:(a) ma waveguide posts;(b) chofananira ndi screw ziwiri
Njira ina yosinthira yawonetsedwa pamwambapa, pomwe nsanamira yachitsulo yozungulira imatambasuka kuchokera mbali imodzi yayikulu kupita ku waveguide, yokhala ndi zotsatira zofanana ndi mzere wachitsulo popereka reactance yolumikizana pamalopo. Nsanamira yachitsulo ikhoza kukhala yogwira ntchito kapena yoyambitsa, kutengera kutalika komwe imatambasuka mu waveguide. Kwenikweni, njira yofananira iyi ndi yakuti pamene nsanamira yachitsulo yotereyi imatambasuka pang'ono mu waveguide, imapereka capacitive susceptance pamalopo, ndipo capacitive susceptance imawonjezeka mpaka kulowa mkati kuli pafupifupi kotala la kutalika kwa wavelength. Pakadali pano, series resonance imachitika. Kulowa kwina kwa nsanamira yachitsulo kumapangitsa kuti inductive susceptance iperekedwe yomwe imachepa pamene kulowetsedwa kumakhala kokwanira. Mphamvu ya resonance pakukhazikitsa kwa midpoint ndi yofanana ndi m'mimba mwake wa mzati ndipo ingagwiritsidwe ntchito ngati fyuluta, komabe, pankhaniyi imagwiritsidwa ntchito ngati band stop fyuluta kuti itumize njira zapamwamba. Poyerekeza ndi kuwonjezera impedance ya mikanda yachitsulo, ubwino waukulu wogwiritsa ntchito nsanamira zachitsulo ndikuti ndizosavuta kusintha. Mwachitsanzo, zomangira ziwiri zingagwiritsidwe ntchito ngati zipangizo zosinthira kuti zigwirizane bwino ndi mafunde.
Zolemetsa zotsutsa ndi zochepetsera mphamvu:
Monga njira ina iliyonse yotumizira mauthenga, ma waveguides nthawi zina amafunika kufananiza bwino ma impedance ndi kusinthidwa kwa katundu kuti azitha kuyamwa mafunde omwe akubwera popanda kuwunikira komanso kuti asakhudzidwe ndi ma frequency. Ntchito imodzi yogwiritsira ntchito ma terminal otere ndi kupanga miyeso yosiyanasiyana ya mphamvu pamakina popanda kutulutsa mphamvu iliyonse.
chithunzi 3 waveguide resistance load(a)single taper(b)double taper
Kutha kwamphamvu kwambiri ndi gawo la dielectric yotayika yomwe imayikidwa kumapeto kwa waveguide ndipo imachepetsedwa (ndi nsonga yolunjika ku mafunde omwe akubwera) kuti isayambitse kuwunikira. Njira yotayika iyi ingakhale m'lifupi lonse la waveguide, kapena ingakhale pakati pa mapeto a waveguide, monga momwe zasonyezedwera pa Chithunzi 3. Taper ikhoza kukhala yocheperako imodzi kapena iwiri ndipo nthawi zambiri imakhala ndi kutalika kwa λp/2, yokhala ndi kutalika konse kwa ma wavelength pafupifupi awiri. Nthawi zambiri imapangidwa ndi mbale za dielectric monga galasi, yokutidwa ndi filimu ya kaboni kapena galasi lamadzi kunja. Pa ntchito zamphamvu kwambiri, ma terminal otere amatha kukhala ndi ma heat sinks owonjezeredwa kunja kwa waveguide, ndipo mphamvu yoperekedwa ku terminal imatha kufalikira kudzera mu heat sink kapena kudzera mu kuzizira kwa mpweya.
chithunzi 4 Chochepetsera vane chosunthika
Zochepetsera mphamvu zamagetsi zimatha kuchotsedwa monga momwe zasonyezedwera pa Chithunzi 4. Zikayikidwa pakati pa waveguide, zimatha kusunthidwa mozungulira kuchokera pakati pa waveguide, komwe zingapereke kuchepa kwakukulu, kupita kumphepete, komwe kuchepa kumachepa kwambiri chifukwa mphamvu yamagetsi ya dominant mode ndi yotsika kwambiri.
Kuchepetsa mphamvu ya waveguide:
Kuchepetsa mphamvu ya ma waveguides kumaphatikizapo zinthu izi:
1. Kuwunikira kuchokera ku kusagwirizana kwa ma waveguide mkati kapena magawo a ma waveguide osakhazikika bwino
2. Kutayika komwe kumachitika chifukwa cha madzi oyenda m'makoma a mafunde
3. Kutayika kwa ma dielectric mu ma waveguides odzazidwa
Ziwiri zomaliza zimafanana ndi kutayika kofanana mu mizere ya coaxial ndipo zonse ndi zazing'ono. Kutayika kumeneku kumadalira zinthu za pakhoma ndi kuuma kwake, dielectric yomwe imagwiritsidwa ntchito komanso kuchuluka kwa magetsi (chifukwa cha zotsatira za khungu). Pa waya wamkuwa, kuchuluka kwake ndi kuyambira 4 dB/100m pa 5 GHz mpaka 12 dB/100m pa 10 GHz, koma pa waya wa aluminiyamu, kuchuluka kwake ndi kochepa. Pa waya wopangidwa ndi siliva, kutayika nthawi zambiri kumakhala 8dB/100m pa 35 GHz, 30dB/100m pa 70 GHz, komanso pafupi ndi 500 dB/100m pa 200 GHz. Kuti muchepetse kutayika, makamaka pamafupipafupi apamwamba kwambiri, ma waveguide nthawi zina amapakidwa golide kapena platinamu (mkati).
Monga tafotokozera kale, waveguide imagwira ntchito ngati fyuluta yodutsa kwambiri. Ngakhale kuti waveguide yokha siitayika, ma frequency omwe ali pansi pa cutoff frequency amachepa kwambiri. Kuchepa kumeneku kumachitika chifukwa cha kuwunikira pakamwa pa waveguide osati kufalikira.
Kulumikiza kwa Waveguide:
Kulumikizana kwa ma waveguide nthawi zambiri kumachitika kudzera mu ma flange pamene zidutswa za ma waveguide kapena zigawo zake zalumikizidwa pamodzi. Ntchito ya flange iyi ndikuwonetsetsa kuti makina olumikizirana ndi magetsi oyenera, makamaka ma radiation akunja otsika komanso kuwunikira kochepa kwamkati.
Mbale:
Ma Waveguide flanges amagwiritsidwa ntchito kwambiri polumikizana ndi ma microwave, ma radar system, ma satellite communications, ma antenna system, ndi zida za labotale mu kafukufuku wasayansi. Amagwiritsidwa ntchito kulumikiza magawo osiyanasiyana a waveguide, kuonetsetsa kuti kutayikira ndi kusokonezana kwaletsedwa, komanso kusunga kulinganiza bwino kwa waveguide kuti zitsimikizire kutumiza kodalirika komanso malo olondola a mafunde a electromagnetic frequency. Waveguide wamba imakhala ndi flange kumapeto onse awiri, monga momwe zasonyezedwera pa Chithunzi 5.
chithunzi 5 (a) flange yosalala; (b) cholumikizira cha flange.
Pa ma frequency otsika, flange idzakulungidwa kapena kulumikizidwa ku waveguide, pomwe pama frequency apamwamba, flatter butt flat flange imagwiritsidwa ntchito. Zigawo ziwiri zikalumikizidwa, ma flange amalumikizidwa pamodzi, koma malekezero ayenera kumalizidwa bwino kuti apewe kusagwirizana mu kulumikizana. N'zoonekeratu kuti n'kosavuta kulumikiza zigawozo bwino ndi kusintha kwina, kotero ma waveguide ang'onoang'ono nthawi zina amakhala ndi ma flanges a ulusi omwe amatha kukulungidwa pamodzi ndi ring nut. Pamene ma frequency akuwonjezeka, kukula kwa waveguide coupling kumachepa mwachibadwa, ndipo kusagwirizana kwa coupling kumakhala kwakukulu poyerekeza ndi kutalika kwa chizindikiro ndi kukula kwa waveguide. Chifukwa chake, kusagwirizana pa ma frequency apamwamba kumakhala kovuta kwambiri.
chithunzi 6 (a) Gawo lopingasa la choke coupling; (b) mawonekedwe a kumapeto kwa choke flange
Pofuna kuthetsa vutoli, pakhoza kukhala mpata wochepa pakati pa ma waveguides, monga momwe zasonyezedwera pa Chithunzi 6. Cholumikizira choko chomwe chili ndi flange wamba ndi choke flange yolumikizidwa pamodzi. Pofuna kubweza kusagwirizana komwe kungachitike, mphete yozungulira yokoka yokhala ndi gawo lozungulira looneka ngati L imagwiritsidwa ntchito mu choke flange kuti igwirizane bwino. Mosiyana ndi ma flange wamba, ma choke flange ndi ogwirizana ndi ma frequency, koma kapangidwe kokonzedwa bwino kangatsimikizire bandwidth yoyenera (mwina 10% ya ma central frequency) yomwe SWR siipitirira 1.05.
Nthawi yotumizira: Januwale-15-2024
