Ke hāʻawi ʻia ka hōʻailona lekiō kiʻekiʻe/microwave i loko o ka PCB kaapuni, ʻo ka poho i hoʻokumu ʻia e ke kaapuni ponoʻī a me ka mea kaapuni e hoʻopuka i kekahi nui o ka wela. ʻOi aku ka nui o ka poho, ʻoi aku ka kiʻekiʻe o ka mana e hele ana i ka mea PCB, a ʻoi aku ka nui o ka wela i hana ʻia. Ke ʻoi aku ka mahana hana o ke kaapuni i ka waiwai i helu ʻia, hiki i ke kaapuni ke hoʻopilikia i kekahi mau pilikia. No ka laʻana, ʻo ka mea hoʻohana maʻamau MOT, ka mea i ʻike nui ʻia i nā PCB, ʻo ia ka wela hana kiʻekiʻe. Ke ʻoi aku ka mahana o ka hana ma mua o ka MOT, e hoʻoweliweli ʻia ka hana a me ka hilinaʻi o ka PCB circuit. Ma o ka hui pū ʻana o ka hoʻohālike electromagnetic a me nā ana hoʻokolohua, ʻo ka hoʻomaopopo ʻana i nā hiʻohiʻona wela o RF microwave PCB hiki ke kōkua i ka pale ʻana i ka hoʻohaʻahaʻa hana kaapuni a me ka hōʻemi ʻana i ka hilinaʻi i hoʻokumu ʻia e nā wela kiʻekiʻe.

ʻO ka hoʻomaopopo ʻana i ke ʻano o ka nalowale ʻana o ka hoʻokomo ʻana i nā mea kaapuni e kōkua i ka wehewehe maikaʻi ʻana i nā mea nui e pili ana i ka hana wela o nā kaapuni PCB kiʻekiʻe. E lawe kēia ʻatikala i ka microstrip transmission line circuit ma ke ʻano he laʻana e kūkākūkā ai i nā kālepa-off e pili ana i ka hana wela o ke kaapuni. I loko o kahi kaapuni microstrip me kahi ʻaoʻao PCB ʻaoʻao ʻelua, ʻo nā poho e komo pū me ka poho dielectric, ka nalowale conductor, ka nalowale o ka radiation, a me ka nalowale leakage. Nui ka ʻokoʻa ma waena o nā ʻāpana poho like ʻole. Me nā ʻokoʻa liʻiliʻi, ʻoi loa ka haʻahaʻa o ka leakage o nā kaapuni PCB kiʻekiʻe. Ma kēia ʻatikala, ʻoiai he haʻahaʻa loa ka waiwai o ka leakage, e mālama ʻia ia no ka manawa.

ʻO ka poho o ka uila

ʻO ka poho o ka radiation e pili ana i nā ʻāpana kaapuni he nui e like me ke alapine hana, ka mānoanoa substrate kaapuni, PCB dielectric mau (relative dielectric constant a i ʻole εr) a me ka hoʻolālā hoʻolālā. E pili ana i nā papahana hoʻolālā, loaʻa pinepine ka nalowale o ka radiation ma muli o ka hoʻololi impedance maikaʻi ʻole i ke kaapuni a i ʻole nā ​​ʻokoʻa o ka neʻe ʻana o ka hawewe electromagnetic i ke kaapuni. Hoʻokomo pinepine ʻia ka wahi hoʻololi impedance kaapuni i ka wahi hānai hōʻailona, ​​wahi impedance step, stub a me ka pūnaewele pili. Hiki i ka hoʻolālā kaapuni kūpono ke hoʻomaopopo i ka hoʻololi impedance maʻalahi, a laila e hōʻemi ana i ka nalowale o ka radiation o ke kaapuni. ʻOiaʻiʻo, pono e hoʻomaopopo ʻia aia ka hiki ke hiki i ka impedance mismatch ke alakaʻi i ka nalowale o ka radiation ma kēlā me kēia interface o ke kaapuni. Mai ka manaʻo o ka hana pinepine, ʻoi aku ka kiʻekiʻe o ke alapine, ʻoi aku ka nui o ka nalowale o ka radiation o ke kaapuni.

ʻO nā ʻāpana o nā mea kaapuni e pili ana i ka nalo radiation ka nui o ka dielectric mau a me ka mānoanoa o nā mea PCB. ʻOi aku ka mānoanoa o ka substrate kaapuni, ʻoi aku ka nui o ka hiki ke lilo i ka nalowale o ka radiation; ʻo ka haʻahaʻa o ka εr o ka mea PCB, ʻoi aku ka nui o ka nalowale o ka radiation o ke kaapuni. Hiki ke hoʻohana ʻia ka hoʻohana ʻana i nā substrate kaapuni lahilahi i mea e hoʻopau ai i ka nalowale o ka radiation i kumu ʻia e nā mea kaapuni εr haʻahaʻa. ʻO ka mana o ka mānoanoa o ka substrate kaapuni a me ka εr i ka nalowale ʻana o ka radiation kaapuni no ka mea he hana hilinaʻi ia. Inā ʻaʻole ʻoi aku ka mānoanoa o ka substrate kaapuni ma mua o 20mil a ʻoi aku ka haʻahaʻa o ka hana ma mua o 20GHz, haʻahaʻa loa ka nalowale o ka radiation. No ka mea ʻoi aku ka haʻahaʻa o ka hapa nui o ka hoʻohālike kaapuni a me nā alapine ana ma kēia ʻatikala ma mua o 20GHz, e haʻalele ka kūkākūkā ma kēia ʻatikala i ka mana o ka nalowale o ka radiation ma ka hoʻomehana kaapuni.

After ignoring the radiation loss below 20GHz, the insertion loss of a microstrip transmission line circuit mainly includes two parts: dielectric loss and conductor loss. The proportion of the two mainly depends on the thickness of the circuit substrate. For thinner substrates, conductor loss is the main component. For many reasons, it is generally difficult to accurately predict conductor loss. For example, the surface roughness of a conductor has a huge influence on the transmission characteristics of electromagnetic waves. The surface roughness of copper foil will not only change the electromagnetic wave propagation constant of the microstrip circuit, but also increase the conductor loss of the circuit. Due to the skin effect, the influence of copper foil roughness on conductor loss is also frequency-dependent. Figure 1 compares the insertion loss of 50 ohm microstrip transmission line circuits based on different PCB thicknesses, which are 6.6 mils and 10 mils, respectively

Nā hualoaʻa i ana a hoʻohālikelike ʻia

Aia i loko o ke kiʻi 1 nā hopena i ana ʻia a me nā hopena hoʻohālike. Loaʻa nā hopena hoʻohālikelike ma o ka hoʻohana ʻana i ka polokalamu helu impedance impedance microwave a Rogers Corporation MWI-2010. Hōʻike ka polokalamu MWI-2010 i nā hoʻohālikelike analytical i loko o nā pepa maʻamau i ke kahua o ka microstrip line modeling. Loaʻa ka ʻikepili hoʻāʻo ma ke Kiʻi 1 e ke ʻano ana ʻokoʻa o ka lōʻihi o kahi mea hoʻoponopono pūnaewele vector. Hiki ke ʻike ʻia mai ka Fig. 1 ʻo nā hopena hoʻohālikelike o ka huina pohō i ke kumu kūpono me nā hopena i ana ʻia. Hiki ke ʻike ʻia mai ke kiʻi, ʻo ka nalowale o ka conductor o ke kaapuni ʻoi aku ka lahilahi (ʻo ka pihi ma ka hema e pili ana i ka mānoanoa o 6.6 mil) ʻo ia ka mea nui o ka huina hoʻokomo. Ke piʻi aʻe ka mānoanoa kaapuni (ʻo ka mānoanoa e pili ana i ka pihi ma ka ʻaoʻao ʻākau he 10mil), ʻo ka nalo dielectric a me ka nalo conductor e hele kokoke mai, a ʻo ia mau mea ʻelua i ka huina hoʻokomo.

ʻO ke kumu hoʻohālike ma ke Kiʻi 1 a me nā ʻāpana mea kaapuni i hoʻohana ʻia i ke kaapuni maoli: dielectric mau 3.66, kumu poho 0.0037, a me ka ʻili o ka ʻili keleawe 2.8 um RMS. Ke emi iho ka roughness o ka ili keleawe ma lalo o ka mea kaapuni like, e emi loa ka lilo o ka conductor o ka 6.6 mil a me 10 mil kaapuni ma ke Kii 1; akā naʻe, ʻaʻole maopopo ka hopena no ke kaapuni 20 mil. Hōʻike ke Kiʻi 2 i nā hopena hoʻāʻo o ʻelua mau mea kaapuni me nā ʻano ʻokoʻa ʻē aʻe, ʻo ia hoʻi ʻo Rogers RO4350B™ mea kaapuni maʻamau me ka ʻeleʻele kiʻekiʻe a me Rogers RO4350B LoPro™ mea kaapuni me ka haʻahaʻa haʻahaʻa.

E like me ka mea i hōʻike ʻia ma ka Figure 1 a me Figure 2, ʻoi aku ka lahilahi o ka substrate kaapuni, ʻoi aku ka kiʻekiʻe o ka hoʻokomo ʻana o ke kaapuni. ʻO ia ke ʻano o ka hānai ʻia ʻana o ke kaapuni me kahi nui o ka mana microwave RF, ʻoi aku ka ʻoi aku o ka wela o ke kaapuni. Ke kaupaona nui ʻia ka pilikia o ka hoʻomehana kaapuni, ma kekahi ʻaoʻao, ʻoi aku ka wela o ke kaapuni lahilahi ma mua o ke kaapuni mānoanoa ma nā pae mana kiʻekiʻe, akā ma ka ʻaoʻao ʻē aʻe, hiki i kahi kaapuni lahilahi ke loaʻa i ka kahe wela ʻoi aku ka maikaʻi ma o ka wela wela. E mālama haʻahaʻa i ka mahana.

I mea e hoʻoponopono ai i ka pilikia wela o ke kaapuni, pono e loaʻa i ke kaʻapuni lahilahi maikaʻi nā hiʻohiʻona penei: kumu poho haʻahaʻa o ka mea kaapuni, ʻili keleawe lahilahi, haʻahaʻa εr a me ka conductivity thermal kiʻekiʻe. Ke hoʻohālikelike ʻia me ka mea kaapuni o ka εr kiʻekiʻe, ʻo ka laulā conductor o ka impedance like i loaʻa ma lalo o ke kūlana o ka εr haʻahaʻa hiki ke ʻoi aku ka nui, he mea pono ia e hōʻemi i ka nalowale o ka conductor o ke kaapuni. Mai ka hiʻohiʻona o ke kaapuni wela dissipation, ʻoiai ka hapa nui o ka PCB kaapuni substrates i loaʻa ka maikaʻi ʻole o ka conductivity wela e pili ana i nā conductors, ʻo ka conductivity thermal o nā mea kaapuni he mea nui loa.

Ua wehewehe ʻia ka nui o nā kūkākūkā e pili ana i ka thermal conductivity o nā substrates circuit ma nā ʻatikala mua, a e haʻi kēia ʻatikala i kekahi mau hopena a me nā ʻike mai nā ʻatikala mua. No ka laʻana, kōkua ka hoohalike a me ka Figure 3 e hoʻomaopopo i nā mea e pili ana i ka hana wela o nā mea kaapuni PCB. Ma ka hoohalike, k ka wela (W/m/K), A ka wahi, TH ka wela o ke kumu wela, TC ka wela o ke kumu anu, a o L ka mamao ma waena o ke kumu wela a me. ke kumu anu.