Nā ʻĀpana Passive i nā Kaapuni RF
Nā mea pale, nā capacitor, nā Antennas. . . . E aʻo e pili ana i nā ʻāpana passive i hoʻohana ʻia i nā ʻōnaehana RF.
ʻAʻole ʻokoʻa loa nā ʻōnaehana RF mai nā ʻano kaapuni uila ʻē aʻe. Pili nā kānāwai like o ka physics, a no laila, loaʻa pū nā ʻāpana kumu i hoʻohana ʻia i nā hoʻolālā RF i nā kaapuni kikohoʻe a me nā kaapuni analog haʻahaʻa alapine.
Eia nō naʻe, pili ka hoʻolālā RF i kahi hoʻonohonoho kūikawā o nā pilikia a me nā pahuhopu, a no laila ke koi nei nā ʻano a me nā hoʻohana ʻana o nā ʻāpana i ka noʻonoʻo kūikawā i ka wā e hana ana mākou i loko o ka pōʻaiapili o RF. Eia kekahi, hana kekahi mau kaapuni i hoʻohui ʻia i nā hana i kikoʻī loa i nā ʻōnaehana RF—ʻaʻole lākou i hoʻohana ʻia i nā kaapuni alapine haʻahaʻa a ʻaʻole paha e maopopo pono ʻia e ka poʻe i loaʻa ka ʻike liʻiliʻi me nā ʻenehana hoʻolālā RF.
Hoʻokaʻawale pinepine mākou i nā ʻāpana ma ke ʻano he hana a i ʻole passive, a kūpono like kēia ʻano hana ma ke kahua o RF. Kūkākūkā ka nūhou i nā ʻāpana passive e pili pono ana i nā kaapuni RF, a uhi ka ʻaoʻao aʻe i nā ʻāpana hana.
Nā Capacitors
E hāʻawi kahi capacitor kūpono i ka hana like no kahi hōʻailona 1 Hz a me kahi hōʻailona 1 GHz. Akā, ʻaʻole kūpono nā ʻāpana, a hiki i nā nonidealities o kahi capacitor ke koʻikoʻi loa i nā alapine kiʻekiʻe.
ʻO "C" ke kūlike me ka capacitor kūpono i kanu ʻia ma waena o nā mea parasitic he nui. Loaʻa iā mākou ke kū'ē palena ʻole ma waena o nā papa (RD), ke kū'ē series (RS), ka inductance series (LS), a me ka capacitance parallel (CP) ma waena o nā pads PCB a me ka mokulele honua (ke manaʻo nei mākou i nā ʻāpana surface-mount; ʻoi aku ka nui ma kēia ma hope).
ʻO ka nonideality koʻikoʻi loa i ka wā e hana ana mākou me nā hōʻailona alapine kiʻekiʻe ʻo ia ka inductance. Manaʻo mākou e emi mau ka impedance o kahi capacitor i ka piʻi ʻana o ke alapine, akā ʻo ke alo o ka inductance parasitic e hoʻoulu ai i ka impedance e emi i lalo i ka alapine resonant ponoʻī a laila hoʻomaka e hoʻonui:
Nā mea kū'ē, a me nā mea ʻē aʻe.
Hiki i nā mea pale ke hoʻopilikia i nā alapine kiʻekiʻe, no ka mea, he inductance series ko lākou, capacitance parallel, a me ka capacitance maʻamau e pili ana me nā pads PCB.
A ke hāpai mai nei kēia i kahi manaʻo koʻikoʻi: ke hana nei ʻoe me nā alapine kiʻekiʻe, aia nā mea kaapuni parasitic ma nā wahi āpau. ʻAʻohe mea maʻalahi a kūpono paha kahi mea resistive, pono nō e hoʻopili ʻia a hoʻopaʻa ʻia i kahi PCB, a ʻo ka hopena he parasitics. Pēlā nō ia i nā ʻāpana ʻē aʻe: inā ua hoʻopili ʻia a hoʻopaʻa ʻia i ka papa, aia nā mea parasitic.
Nā kristal
ʻO ke ʻano o RF ka hoʻopunipuni ʻana i nā hōʻailona alapine kiʻekiʻe i mea e hōʻike ai lākou i ka ʻike, akā ma mua o ko mākou hoʻopunipuni ʻana pono mākou e hana. E like me nā ʻano kaapuni ʻē aʻe, ʻo nā kristal kahi ala nui o ka hana ʻana i kahi kuhikuhi alapine paʻa.
Eia nō naʻe, i ka hoʻolālā kikohoʻe a me ka hoʻolālā hōʻailona hui ʻia, ʻo ia ka manawa pinepine ʻaʻole pono nā kaapuni kristal i ka pololei e hiki ai i kahi kristal ke hāʻawi, a no laila he mea maʻalahi ke lilo i mea mālama ʻole e pili ana i ke koho kristal. ʻO kahi kaapuni RF, i ka hoʻohālikelike ʻana, hiki ke loaʻa nā koi alapine koʻikoʻi, a koi kēia ʻaʻole wale no ka pololei alapine mua akā ʻo ke kūpaʻa alapine.
ʻO ke alapine oscillation o kahi kristal maʻamau he mea maʻalahi ia i nā loli o ka mahana. ʻO ka hopena o ka paʻa ʻole o ke alapine e hoʻokumu i nā pilikia no nā ʻōnaehana RF, ʻoiai nā ʻōnaehana e hōʻike ʻia i nā loli nui o ka mahana ambient. No laila, pono paha kahi ʻōnaehana i kahi TCXO, ʻo ia hoʻi, kahi oscillator kristal i uku ʻia e ka mahana. Hoʻokomo kēia mau mea hana i ka circuitry e uku no nā loli alapine o ke kristal:
Nā Antennas
He ʻāpana passive ka antenna i hoʻohana ʻia e hoʻololi i kahi hōʻailona uila RF i ka radiation electromagnetic (EMR), a i ʻole ka ʻaoʻao ʻē aʻe. Me nā ʻāpana ʻē aʻe a me nā alakaʻi e hoʻāʻo mākou e hōʻemi i nā hopena o EMR, a me nā antennas e hoʻāʻo mākou e hoʻomaikaʻi i ka hana ʻana a i ʻole ka loaʻa ʻana o EMR e pili ana i nā pono o ka noi.
ʻAʻole maʻalahi ka ʻepekema antenna. Hoʻopili nā kumu like ʻole i ke kaʻina hana o ke koho ʻana a i ʻole ka hoʻolālā ʻana i kahi antenna i kūpono loa no kahi noi kikoʻī. Loaʻa iā AAC ʻelua mau ʻatikala (kaomi ma aneʻi a ma aneʻi) e hāʻawi ana i kahi hoʻolauna maikaʻi loa i nā manaʻo antenna.
Hoʻopili ʻia nā alapine kiʻekiʻe e nā pilikia hoʻolālā like ʻole, ʻoiai hiki i ka ʻāpana antenna o ka ʻōnaehana ke lilo i mea pilikia ʻole i ka piʻi ʻana o ke alapine, no ka mea, ʻae nā alapine kiʻekiʻe i ka hoʻohana ʻana i nā antenna pōkole. I kēia mau lā he mea maʻamau ka hoʻohana ʻana i kahi "antenna chip," i hoʻopaʻa ʻia i kahi PCB e like me nā ʻāpana maʻamau o ka ʻili, a i ʻole kahi antenna PCB, i hana ʻia ma ka hoʻohui ʻana i kahi kaha i hoʻolālā kūikawā ʻia i loko o ka hoʻolālā PCB.
Hōʻuluʻulu manaʻo
He mea maʻamau kekahi mau ʻāpana i nā noi RF wale nō, a pono e koho ʻia a hoʻokō pono ʻia nā mea ʻē aʻe ma muli o kā lākou ʻano hana alapine kiʻekiʻe ʻaʻole kūpono.
Hōʻike nā ʻāpana passive i ka pane alapine (frequency) nonideal ma muli o ka inductance parasitic a me ka capacitance.
Hiki i nā noi RF ke koi aku i nā kristal i ʻoi aku ka pololei a/a i ʻole ke kūpaʻa ma mua o nā kristal i hoʻohana pinepine ʻia i nā kaapuni kikohoʻe.
He mau ʻāpana koʻikoʻi nā antennas e pono e koho ʻia e like me nā ʻano a me nā koi o kahi ʻōnaehana RF.
ʻO Si Chuan Keenlion Microwave kahi koho nui i nā hoʻonohonoho narrowband a me broadband, e uhi ana i nā alapine (frequencies) mai 0.5 a 50 GHz. Ua hoʻolālā ʻia lākou e lawelawe mai 10 a 30 watts ka mana hoʻokomo i loko o kahi ʻōnaehana hoʻoili 50-ohm. Hoʻohana ʻia nā hoʻolālā Microstrip a i ʻole stripline, a ua hoʻonohonoho pono ʻia no ka hana maikaʻi loa.
Ka manawa hoʻouna: Nov-03-2022
