Frequency-Tunable Graphene Patch Antenna in Terahertz Regime

Fig. 9. Radiation patterns of graphene antenna under different resonance frequencies. (a) 695.55 GHz; (b) 698.10 GHz; (c) 701.55 GHz; (d) 703.15 GHz; (e) 705.05 GHz

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Fig. 10. Chemical potential versus resonance frequency

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Table 1. Parameters of frequency-reconfigurable graphene antenna

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Table 1. Parameters of frequency-reconfigurable graphene antenna

Component	Parameter	Value /μm
Patch	Length L	98.5
Patch	Width W	133.2
Microstrip line	Length L'₁	16.98
	Length L'₂	30
	Length L'₃	13
	Width W'₁	6
	Width W'₂	6
	Width W'₃	20
Substrate (polyimide)	Length L_s	210
	Width W_s	433.5
	Height h	18
Silicon	Height h₁	0.525

Table 2. Radiation performances of frequency-reconfigurable graphene antenna

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Table 2. Radiation performances of frequency-reconfigurable graphene antenna

Resonance frequency /GHz	Chemical potential /eV	Absolute impedance bandwidth /GHz	Relative impedance bandwidth /%	Maximum radiation gain /dB	Directivity factor /dB	Radiation efficiency /%
695.55	0	678.25-713.65	5.08	5.82	8.01	72.56
698.10	0.1	680.75-715.95	5.04	6.33	8.02	79.00
701.55	0.25	685.10-718.55	4.77	6.66	8.01	83.10
703.15	0.45	687.05-720.05	4.70	6.80	8.01	84.80
705.05	1	689.95-721.75	4.63	6.92	8.01	86.48

Table 3. Parameters in equivalent circuit of frequency-reconfigurable graphene antenna

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Table 3. Parameters in equivalent circuit of frequency-reconfigurable graphene antenna

$\begin{matrix} {f_{res}}_{} \end{matrix}$ /GHz	$\begin{matrix} {μ_{c}}_{} \end{matrix}$ /eV	$\begin{matrix} {G_{s 1}}_{} \end{matrix}$ /μS	$\begin{matrix} {G_{s 2}}_{} \end{matrix}$ /mS	$\begin{matrix} {C_{s 1}}_{} \end{matrix}$ /aF	$\begin{matrix} {C_{s 2}}_{} \end{matrix}$ /fF	C /fF
695.55	0	11.7072	1.0598	409.10	2.3689	1.3
698.10	0.1	11.7946	1.0677	408.99	2.3387	0.2
701.55	0.25	11.9107	1.0782	408.85	2.3278	0.9
703.15	0.45	11.9610	1.0827	408.79	2.3240	0.9
705.05	1	12.0286	1.0889	408.71	2.3212	0.9

Table 4. Radiation performances of existing antennas from different references

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Table 4. Radiation performances of existing antennas from different references

Parameter	Ref. [11]		Ref. [23]	Ref. [24]	Ref. [25]	Ref. [26]
Resonance frequency /GHz	750	770	6000	1500	720	1425	1325
Impedance bandwidth /%	6.67	6.67	12.83	-	13.36	-	-
Maximum radiation gain /dB	5.09	5.07	3.27	0	3.852	-	-
Directivity factor /dB	5.71	5.70	7.56	-	6.456	-	-
Radiation efficiency /%	86.58	86.43	37.17	-	54.9	43	44.5