[1] SHI S C, PAINE S, YAO Q, et al. Terahertz and far-infrared windows opened at dome a in antarctica[J]. Nature Astronomy, 2016, 1(1):1-7.

[3] KOOI J, CHAMBERLIN R, MONJE R, et al. Balanced receiver technology development for the caltech submillimeter observatory[J]. IEEE Transactions on Terahertz Science and Technology, 2012, 2(1):71-82.

[4] DING J Q, MAESTRINI A, GATILOVA L, et al. A 300 GHz power-combined frequency doubler based on E-plane 90°- hybrid and Y-junction[J]. Microwave and Optical Technology Letters, 2020, 62(8):2683-2691.

[5] DING J Q, SHI S C, ZHOU K, et al. WR-3 band quasi-elliptical waveguide filters using higher order mode resonances[J]. IEEE Transactions on Terahertz Science and Technology, 2017, 7(3):302-309.

[6] DING J Q, ZHAO Y, GE J X, et al. A 90° waveguide hybrid with low amplitude imbalance in full W-band[J]. Journal of Infrared, Millimeter, and Terahertz Waves, 2019, 40(3):429-434.

[7] LI Y, KIRBY P L, OFFRANC O, et al. Silicon micromachined W-band hybrid coupler and power divider using DRIE technique[J]. IEEE Microwave and Wireless Components Letters, 2008, 18(1):22-24.

[8] KUROIWA K, GONZALEZ A, KOYANO M, et al. Short-slot hybrid coupler using linear taper in W-band[J]. Journal of Infrared, Millimeter, and Terahertz Waves, 2013, 34(12):815-823.

[9] DESMARIS V, MELEDIN D, PAVOLOTSKY A, et al. All-metal micromachining for the fabrication of sub-millimetre and THz waveguide components and circuits[J]. Journal of Micromechanics and Microengineering, 2008, 18(9):095004.

[10] LIU S, HU J, ZHANG Y, et al. Silicon micromachined waveguide quadrature-hybrid coupler at terahertz frequency band[J]. Journal of Infrared Millimeter & Terahertz Waves, 2015, 36(8):709-719.

[12] DENG J Y, DUAN J P, LIU R, et al. A 3 dB E-plane waveguide directional coupler employing micromachining technique for terahertz application[J]. Microwave and Optical Technology Letters, 2020, 62(11):1-7.

[13] LIU S, HU J, ZHANG Y, et al. Sub-millimeter-wave 10 dB directional coupler based on micromachining technique[J]. International Journal of Antennas and Propagation, 2015(4):1-8.

[14] SRIKANTH S, KERR A R. Waveguide quadrature hybrids for ALMA receivers[EB/OL]. (2001-01-17)[2021-04-01]. http://www.alma.nrao.edu/memos/html-memos/alma343.

[16] RASHID H, DESMARIS V, BELITSKY V, et al. Design of wideband waveguide hybrid with ultra-low amplitude imbalance[J]. IEEE Transactions on Terahertz Science and Technology, 2016, 6(1):83-90.

[17] REED J. The multiple branch waveguide coupler[J]. IEEE Transactions on Microwave Theory and Techniques, 1958, 6(4): 398-403.

[18] NIU Z, LI D, ZHANG B, et al. Mode analyzing method for fast design of branch waveguide coupler[J]. IEEE Transactions on Microwave Theory and Technology, 2019, 67(12):4733–4740.