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

Radiation loss depends on many circuit parameters such as operating frequency, circuit substrate thickness, PCB dielectric constant (relative dielectric constant or εr) and design plan. As far as design schemes are concerned, radiation loss often stems from poor impedance transformation in the circuit or electromagnetic waves in the circuit. The difference in transmission. Circuit impedance transformation area usually includes signal feed-in area, step impedance point, stub and matching network. Reasonable circuit design can realize smooth impedance transformation, thereby reducing the radiation loss of the circuit. Of course, it should be realized that there is the possibility of impedance mismatch leading to radiation loss at any interface of the circuit. From the point of view of operating frequency, usually the higher the frequency, the greater the radiation loss of the circuit.

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.

Ma hope o ka haʻalele ʻole ʻana i ka nalowale o ka radiation ma lalo o 20GHz, ʻo ka nalowale o ka hoʻokomo ʻana o kahi kaapuni laina microstrip ʻelua mau ʻāpana: ka poho dielectric a me ka nalowale conductor. ʻO ka māhele o nā mea ʻelua e pili ana i ka mānoanoa o ka substrate kaapuni. No nā substrate ʻoi aku ka lahilahi, ʻo ka nalowale conductor ka mea nui. No nā kumu he nui, he paʻakikī ke wānana pololei i ka nalowale o ka conductor. No ka laʻana, he mana nui ka ʻili o kahi conductor i nā hiʻohiʻona hoʻoili o nā hawewe electromagnetic. ʻAʻole e hoʻololi wale ka ʻili o ka ʻili keleawe i ka hoʻolaha ʻana o ka nalu electromagnetic mau o ka microstrip circuit, akā e hoʻonui pū i ka nalowale o ka conductor. Ma muli o ka hopena o ka ʻili, ʻo ka hopena o ka ʻeleʻele keleawe keleawe i ka nalowale o ka conductor e hilinaʻi pū ʻia. Hoʻohālikelike ka Figure 1 i ka nalowale o ka hoʻokomo ʻana o 50 ohm microstrip transmission line circuit ma muli o nā mānoanoa PCB like ʻole, ʻo ia ka 6.6 mils a me 10 mils, kēlā me kēia.

The simulation results are obtained using Rogers Corporation’s MWI-2010 microwave impedance calculation software. The MWI-2010 software quotes the analytical equations in the classic papers in the field of microstrip line modeling. The test data in Figure 1 is obtained by the differential length measurement method of a vector network analyzer. It can be seen from Fig. 1 that the simulation results of the total loss curve are basically consistent with the measured results. It can be seen from the figure that the conductor loss of the thinner circuit (the curve on the left corresponds to a thickness of 6.6 mil) is the main component of the total insertion loss. As the circuit thickness increases (the thickness corresponding to the curve on the right is 10mil), the dielectric loss and the conductor loss tend to approach, and the two together constitute the total insertion loss.

The circuit material parameters used in the simulation model and the actual circuit are: dielectric constant 3.66, loss factor 0.0037, and copper conductor surface roughness 2.8 um RMS. When the surface roughness of the copper foil under the same circuit material is reduced, the conductor loss of the 6.6 mil and 10 mil circuits in Figure 1 will be significantly reduced; however, the effect is not obvious for the 20 mil circuit. Figure 2 shows the test results of two circuit materials with different roughness, namely Rogers RO4350B™ standard circuit material with high roughness and Rogers RO4350B LoPro™ circuit material with low roughness.

For thinner substrates, the use of smooth copper foil can significantly reduce the insertion loss. For the 6.6mil substrate, the insertion loss is reduced by 0.3 dB due to the use of smooth copper foil at 20GHz; the 10mil substrate is reduced by 0.22 dB at 20GHz; and the 20mil substrate, the insertion loss is only reduced by 0.11 dB.

This means that when the circuit is fed with a certain amount of RF microwave power, the thinner the circuit will generate more heat. When comprehensively weighing the issue of circuit heating, on the one hand, a thinner circuit generates more heat than a thick circuit at high power levels, but on the other hand, a thinner circuit can obtain more effective heat flow through the heat sink. Keep the temperature relatively low.

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.