Additive Manufacturing of Monolithic Microwave Dielectric Ceramic Filters via Digital Light Processing
, Chen Jiao 1, Yun Ye 1, Deqiao Xie 1, Changjiang Wang 2, Meng Xiao 3 and Jianfeng Zhao 1Round 1
Reviewer 1 Report
Comments and Suggestions for Authors
The paper is interesting especially for using an effective method for manufacturing monolithic microwave dielectric ceramic filters with complex and precious structures.
What follows is a list of suggested changes that I would love to see addressed before the paper is published.
1.- There are many errors, typos, etc that should be fixed before publication, for example:
a.- At the end of line 133 appears "In order to shield the fifilter..."
b.- On line 198 you write "Fig. 5 shows that when the sintering temperature is 1400 °C, ..." but in that figure, that temperature does not appear. It is better to set the temperatures associated with the images in that Fig. 5
c.- On the line 243 you write "As shown in Fig. 1,". Maybe it's Fig 2. ?
d.- In the equation 3 appears E1--->Ei.
2.- On line 291 you write "electromagnetic simulation process. " but it does not explain how you performed that simulation, what tool you use ?, and what are the parameters used ?.
3.- The composition and condition found to obtain the optimal objective functions: 1.- small dielectric constant, 2.- quality factor as large as possible,
and 3.- frequency temperature coefficient τf near to zero. At that optimum point obtained what is the influence on other important properties such as thermal conductivity, to avoid overheating ?.
thank you
Author Response
Point 1: 1.- There are many errors, typos, etc that should be fixed before publication, for example:
a.- At the end of line 133 appears "In order to shield the fifilter..."
b.- On line 198 you write "Fig. 5 shows that when the sintering temperature is 1400 °C, ..." but in that figure, that temperature does not appear. It is better to set the temperatures associated with the images in that Fig. 5
c.- On the line 243 you write "As shown in Fig. 1,". Maybe it's Fig 2. ?
d.- In the equation 3 appears E1--->Ei.
Response 1: Thank you for your advice. We have corrected the errors and typos. At the end of line 133, we have replaced “fifilter” with “filter”. On the line 198, we have modified the sentence to “Fig. 5(a1) shows that when the sintering temperature is 1400 °C, ... However, as is shown in Fig. 5(b1), ... It can be observed from Fig. 5(a3) and Fig. 5(b3) that when the sample is sintered at 1550 °C for 2 h and annealed at 1000 °C for 5 h, ...” And we have revised Figure 5’s caption with “SEM images of 0.9 Al2O3 – 0.1 TiO2 ceramics sintered at (a1) 1400 °C, (a2) 1500 °C, (a3) 1550 °C, (a4) 1600 °C. (b1), (b2), (b3) and (b4) are post-annealed samples of (a1), (a2), (a3), and (a4), respectively.” On the line 243, we have replaced “Fig. 1” with “Fig. 2”. In the equation, we have revised “E1” with “Ei”.
Point 2: 2.- On line 291 you write "electromagnetic simulation process. " but it does not explain how you performed that simulation, what tool you use ?, and what are the parameters used ?.
Response 2: Thank you for your suggestion. We have added the explanation that the electromagnetic simulation tool used for simulation was High Frequency Structure Simulator (HFSS), and we have added detailed steps for HFSS simulation. In these steps, we have mentioned essential parameter settings. For details, please see section 2.2. ‘Design and simulation of the microwave dielectric ceramic filter’.
Point 3: 3.- The composition and condition found to obtain the optimal objective functions: 1.- small dielectric constant, 2.- quality factor as large as possible,and 3.- frequency temperature coefficient τf near to zero. At that optimum point obtained what is the influence on other important properties such as thermal conductivity, to avoid overheating ?
Response 3: Thank you for your reminder. We have added the introduction of thermal conductivity of 0.9 Al2O3 - 0.1 TiO2, which has been highlighted. The melting temperature of 0.9 Al2O3 – 0.1 TiO2 is around 1900 °C, which can be an indirect indicator of strong interatomic bonding, a prerequisite for high thermal conductivity. At that optimum point obtained, 0.9 Al2O3 – 0.1 TiO2 possesses almost all features of high thermal conductivity of a typical ceramics, such as simple crystal structure, low atomic mass, strong interatomic forces, high atomic packing density, comparable atomic weight differences among the components in the composition etc. . Due to its great thermal conductivity, it can avoid overheating.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Preparation of microwave dielectric ceramic filter need to explained still better. Fabricated filter is not presented properly HFSS simulated schematic or layout is not provided How two SMA connectors are mounted ? have you considered parasitic effects of it ? Test setup should be displayed using Keysight N5247A at least as supplement S- parameters S22 and S12 is not displayed What EM Models are used to simulate ? Manuscript is quite difficult to understand (0.9 Al2O3 – 0.1 TiO2) how this combination is useful to make filtering action Explanation for the microwave part should be improvedAuthor Response
Point 1: Preparation of microwave dielectric ceramic filter need to explained still better.
Response 1: Thank you for your advice. We have further explained the preparation process. And we have described that the DLP printing machine is developed by Nanjing University of Aeronautics and Astronautics. The light source of the DLP printer can emit ultraviolet light at the wavelength of 405 nm. The size of the experimental molding substrate was 60 mm × 80 mm, and its z axis accuracy is 10 μm. In addition, we have added a schematic view to explain its printing process.
Point 2: Fabricated filter is not presented properly HFSS simulated schematic or layout is not provided.
Response 2: Thank you for your reminder. As shown in Fig. 2, We have added the prototype of the designed microwave dielectric ceramic filter. We have added detailed steps for HFSS simulation. In these steps, we have mentioned essential parameter settings. For details, please see section 2.2. ‘Design and simulation of the microwave dielectric ceramic filter’.
Point 3: How two SMA connectors are mounted ? Have you considered parasitic effects of it ?
Response 3: Thank you for your reminder. We are sorry that we didn’t show the mounting position of two SMA connectors clearly. As shown in Fig. 5, We have added the schematic diagram. And we have considered parasitic effects of it. Because the coaxial connectors were built when modeling, and then simulated. Parasitic capacitance and parasitic inductance have been taken into account. Fortunately, they did not have any negative impact.
Point 4: Test setup should be displayed using Keysight N5247A at least as supplement S- parameters S22 and S12 is not displayed.
Response 4: Thank you for your advice. We have supplemented the measured results of S22 and S12.
Point 5: What EM Models are used to simulate ?
Response 5: Thank you for your question. We have supplemented that the fundamental resonance is the TM01δ mode. And We have added the prototype of the designed microwave dielectric ceramic filter. We have added detailed steps for HFSS simulation. In these steps, we have mentioned essential parameter settings. For details, please see section 2.2. ‘Design and simulation of the microwave dielectric ceramic filter’.
Point 6: Manuscript is quite difficult to understand (0.9 Al2O3 – 0.1 TiO2) how this combination is useful to make filtering action. Explanation for the microwave part should be improved.
Response 6: Thank you for your question. Since the microwave communication device is used in different ambient temperatures. If the resonant frequency of the microwave dielectric material changes greatly with temperature, the carrier signal will drift at different temperatures, thereby affecting the performance of the device. It is required that the resonant frequency of the material hardly change with temperature. A certain amount of TiO2 is usually added to form 0.9 Al2O3 – 0.1 TiO2 composite ceramics, allowing a value of τf tending to zero, which ensures that the filter’s resonant center frequency does not drift with temperature. At the same time, 0.9 Al2O3 – 0.1 TiO2 composite ceramics exhibits outstanding dielectric properties. In this article, we first simulated the filter’s performance using parameters of 0.9 Al2O3 – 0.1 TiO2’s dielectric properties. Simulation results indicated that the material of 0.9 Al2O3 – 0.1 TiO2 were useful to make filtering action. Then we measured the fabricated filter’s filtering performance, results of which were consistent with the measured ones. We have added some explanations for the microwave part according to your advice.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The responses of the S12 and S22 parameters are clear If possible targeted application can be added in the conclusion Electromagnetic simulation process like MOM, FEM, FDTD can be mentioned The fabricated filter is acknowledgedAuthor Response
Thank you for your approval and suggestions.
Point 1: If possible targeted application can be added in the conclusion.
Response 1: Thank you for your advice. We have added its targeted applications in conclusion, such as cellular mobile network systems, communication base stations, television satellite receiving systems, satellite communication, and radar systems, etc.
Point 1: Electromagnetic simulation process like MOM, FEM, FDTD can be mentioned.
Response 2: Thank you for your advice. We have added that electromagnetic simulation process was based on finite element method (FEM).
According to your advice, we have our manuscript checked by a professional English editing service.
Author Response File: Author Response.pdf
