(14)
Figure 3(b) shows the susceptance of YL andYt. It can be concluded from (11) that there are
two cases in which resonance occurs. The first circumstance is that the
susceptance of YL equals to the negative value of
the susceptance of Yt , that is whenBL =-Bt . As shown in
Fig.3(b), three resonance points correspond to this case, and they aref1 , f3 andf4 respectively. Under the above resonance
points, the value of the susceptance for YLcounteracts the susceptance for Yt . In the second
case, the susceptance of YL equals to the
susceptance of YT equals to zero, that is whenBL =Bt =0. As observed in
Fig.3(b), resonance point f2 corresponds to this
situation. Compared to the three resonant points in other absorbers, the
proposed PIUWA has an extra resonance forBL =-Bt . It is because an
impedance jump occurs when the shorter dipole and the conductor-backed
vertical substrate goes through the cascaded transmission lineh2 . The impedance jump makesBL produce another negative point to cancel outBt and creates a new resonant point at the high
frequency thus expanding the bandwidth of the PIUWA. As for the five
resonance points of the dual polarization model in Fig.4, the addition
of a resonance is due to the interaction of the two sets of resonant
units on the two adjacent surfaces.
Finally, the polarization dependence and oblique incidence stability of
the proposed PIUWA are investigated. The simulated PIUWA reflection
coefficients at different incidence angles are shown in Fig.4. It can be
seen from the figure that despite for some deteriorates at large angle
incidence for the high frequencies above 20GHz, the proposed PIUWA shows
a good angular stability under full-wave polarizations over an ultrawide
absorption band within 45° while maintaining S11≤-10dB which means a
good absorptance batter than 90%.
Conclusion: This paper introduces a novel methodology for
designing an ultra-wideband circuit analog (CA) absorber. Utilizing this
approach, we have designed a compact ultra-wideband absorber. The
proposed PIUWA exhibits a broad absorption band ranging from 4 to
24.53GHz and maintains a small footprint of
0.10λL×0.10λL×0.11λL(where λL denotes the wavelength at the lowest
absorption frequency). A prototype of the PIUWA was subsequently
fabricated and tested. The experimental measurements effectively
corroborated the simulated results of the designs, thereby validating
our approach.
Acknowledgments: This work is supported by National Key Research
and Development Program of China (No. 2020YFB1806405), National Natural
Science Foundation of China (No. 12004258), Shanghai Science and
Technology Innovation Action Plan (No. 21511101403) and Major Key
Project of PCL (No. PCL2021A17).
Kun Xue, Yifeng Qin, Haoliang Sun and
Shaohua Dong (Peng Cheng
National Lab, Shenzhen, Guangdong, China ) E-mail:
xuek@pcl.ac.cn,
qinyf@pcl.ac.cn,
sunhl@outlook.com,lightdong@yeah.net.
Hongyi Zhu (Shanghai Engineering Research Center for Broadband
Technologies and Applications, Shanghai, China ) E-mail: zhuhy@pcl.ac.cn
Min Han (Academy of
Military Sciences, Beijing, China ) E-mail: hanminchina@163.com.
Hongyi Zhu (Shanghai Engineering Research Center for Broadband
Technologies and Applications, Shanghai, China ) E-mail: zhuhy@
pcl.ac.cn.
* Corresponding author: Min Han, Shaohua Dong