Transponder Designs for Harmonic Radar Applications

Table 1

Summary on the features of some harmonic radar tags found in the literature.

Reference	& 2 (GHz)	Transponder dimensions	Mixing element	Type of matching
[11]	1 & 2	mm^2 ()	Schottky	Direct
[19]	9.41 & 18.82	16 mm, 1 mm	Schottky	Direct
[20]	0.917 & 1.834	50 mm, 0.152 mm	Schottky	Direct
[29]	1.59 & 3.18	cm^2 ()	Nonspecified diode	Stepped-impedance microstrip lines
[30]	2.45 & 5.9	15.7 cm, 1.5 cm	Schottky	Direct
[31]	5.9–6 & 11.8–12	mm^2 ()	Schottky	Direct
[33]	38.5 & 77	mm^2 ()	Schottky	Direct
[41]	0.914 & 1.828	mm^2 ()	Schottky	Direct
[42]	2.4 & 4.8	30 mm (diagonal)	Schottky	Impedance transformer based on microstrip lines
[45]	1.3 & 2.6	mm^2 ()	Schottky	Direct and external matching