Me ka ʻole o kahi kānana ma ka ʻaoʻao mua o RF, e hoʻemi nui ʻia ka hopena o ka loaʻa ʻana. Pehea ka nui o ka hoʻēmi? Ma keʻano laulā, me nā antennas maikaʻi, e ʻoi aku ka ʻino o ka mamao ma ka liʻiliʻi he 2 mau manawa. Eia kekahi, ʻo ke kiʻekiʻe o ka antenna, ʻoi aku ka ʻino o ka loaʻa ʻana! No ke aha mai ia? No ka mea, ua piha ka lani o kēia lā i nā hōʻailona he nui, ke ālai nei kēia mau hōʻailona i ka ʻōmole loaʻa mua. ʻOiai he mea nui ka kānana mua, pehea e hana ai i ka kānana mua? ʻO ke kumu kiʻekiʻe o ka ʻoihana Rf e aʻo iā ʻoe! Eia naʻe, ʻaʻole maʻalahi ka hoʻohui ʻana i ka kānana mua no ka hui 435MHz. E hoʻomaka kākou i ka nānā ʻana
ʻO kēia kahi hoʻonohonoho o nā kānana band-pass Chebyshev me kahi hui capacitor luna a me ke alapine waena o 435MHz. Ma muli o ka hoʻohana ʻana i nā inductors chip i loaʻa i ke kālepa (nona ka waiwai Q a hiki i ka 70), nui loa ka pohō hoʻokomo, e hiki ana i ka -11db, a ʻo kekahi piʻo ʻo ia ka reflection (hiki ke hoʻololi ʻia i mau nalu kū). No laila, ua pilikia nui ka ʻike o ka mea loaʻa, no ka mea, pili pono ka ʻike o ka mea loaʻa i ka helu walaʻau o ka pae mua o ka hoʻonui kiʻekiʻe, ʻoiai inā maikaʻi ka ʻenehana, e like me ke kiʻi walaʻau o ka hoʻonui kiʻekiʻe hiki ke hoʻomalu ʻia i 0.5, akā ʻo ka pohō plug o ke kānana mua e hoʻonui maoli i ka helu walaʻau ma 11db. No laila, he mea kakaikahi ka ʻike ʻana i hoʻohana ʻia e like me kēia. E nānā hou i kēia kiʻi:
E mālama i nā palena ʻē aʻe, ua pani ʻia ka inductor e kahi ʻōwili hakahaka maikaʻi aʻe, ʻoiai he nui ka leo, akā lilo ka pohō hoʻokomo ma kahi o -5, kahi mea hiki ke hoʻohana ʻia, akā paʻakikī loa ka hana ʻana. No ka mea: ʻO ka capacitance coupling ma luna he 0.2P wale nō, a ʻaʻole maʻalahi ke kūʻai ʻana i ka capacitance o kēia hiki, no laila hiki iā ʻoe ke kahakiʻi wale i ka capacitor ma ka PCB, kahi e lawe mai ai i ka paʻakikī i ka holomua 1. ʻOiai ʻaʻole maikaʻi loa ka inductor 12nH i ka wili, a pono ia e hakahaka a interwound, a ʻaʻole maikaʻi ke haku inā ʻaʻohe ʻike lawa. He nui iki nō ka inductance, ʻoi aku ka naʻauao o nā palena o kēlā mau capacitors, a e hoʻopilikia iki ka loli i ka hana. No laila pehea inā hiki iā ʻoe ke hoʻomau i ka hoʻonui ʻana i ka waiwai Q o ka inductor, a aia kekahi ala e hoʻomau ai i ka hoʻemi ʻana i ka capacitance coupling? A laila e hoʻemi iki i ka bandwidth. Penei ke kūlana:
ʻO ka waiwai inductance Q o kēia kiʻi i lilo koke i 1600, a lilo pū ka inductance i mea nui aʻe, lilo ka pakuhi i mea nani loa, hiki i kēia kānana ke hōʻoia i ka selectivity a me ka ʻike o ka mea loaʻa a me nā ʻōkuhi ʻē aʻe, inā ʻaʻohe noʻonoʻo o ka hoʻohana ʻana i ka ikehu ma ke kua o kahi ʻāpana IC, huki koke i ka mamao i luna. ʻOi aku ka maikaʻi o ka hana, akā ʻoi aku ka nui o ka kānana microstrip
Hoʻolālā kānana wili kūpono No kēia kānana wili, ʻoi aku ka liʻiliʻi o ka poʻe e hoʻolālā maoli ma Kina, a hiki ke hoʻohui maikaʻi ʻia ka polokalamu. ʻO ka mea mua, ke hōʻike nei ke kiʻi ma mua i ka kānana wili maoli no nā polokalamu kelepona 435MHz. ʻO ka ʻoiaʻiʻo, pono e hana pono ʻia nā kānana maikaʻi aʻe, e hoʻolālā mākou i nā kānana 2-cavity a me 4-cavity kiʻekiʻe no kēia mīkini hoʻāʻo.
Ka manawa hoʻouna: Iulai-17-2024