© The Institution of Engineering and Technology
This Letter reports a high isolation diplexer using stub-loaded resonators (SLRs). Each SLR can generate one transmission pole and one transmission zero (TZ). By changing the length of the open stub, the frequency of the TZ can be adjusted. The upper channel filter using the capacitive coupled SLRs can have TZs above the passband, while the lower channel filter using inductive coupled SLRs can have TZs below the passband. With those TZs, the isolation of the diplexer is greatly improved. A high isolation diplexer is designed and fabricated to validate the design concept.
References
-
-
1)
-
3. Khan, A.A., Mandal, M.K.: ‘Design of planar diplexers with improved isolation using the tunable transmission zeros of a dual-mode cavity filter’, Microw. Antennnas. Prop., 2017, 11, (11), pp. 1587–1593 (doi: 10.1049/iet-map.2016.0692).
-
2)
-
1. Cheng, F., Lin, X.Q., Zhu, Z.B., et al: ‘High isolation diplexer using quarter-wavelength resonator filter’, Electron. Lett., 2012, 48, (6), pp. 330–331 (doi: 10.1049/el.2012.0031).
-
3)
-
5. Tu, W.-H.: ‘Compact double-mode cross-coupled microstrip bandpass filter with tunable transmission zeros’, Microw. Antennas Propag., 2008, 2, (4), pp. 373–377 (doi: 10.1049/iet-map:20070203).
-
4)
-
4. Gómez-García, R., Muñoz-Ferreras, J., Psychogiou, D.: ‘Quasi-elliptic-type multiplexer design without cross coupling’, Microw. Wirel. Compon. Lett., 2018, 28, (9), pp. 801–803 (doi: 10.1109/LMWC.2018.2856403).
-
5)
-
7. Xiao, J., Zhang, M., Ma, J.: ‘A compact and high-isolated multiresonator-coupled diplexer’, Microw. Wirel. Compon. Lett., 2018, 28, (11), pp. 999–1001 (doi: 10.1109/LMWC.2018.2873214).
-
6)
-
1. Guan, X., Huag, W., Ren, B.: ‘Miniaturized high-temperature superconducting diplexer using common resonator and cross coupling structure’, Trans. Appl. Supercond., 2017, 27, (4), pp. 1–4 (doi: 10.1109/TASC.2016.2631906).
-
7)
-
6. Matthaei, G.L., Young, L., Jones, E.M.T.: ‘Microwave filters, impedance-matching networks, coupling structures’ (Artech House, Norwod, MA, 1980).
http://iet.metastore.ingenta.com/content/journals/10.1049/el.2019.1201
Related content
content/journals/10.1049/el.2019.1201
pub_keyword,iet_inspecKeyword,pub_concept
6
6