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## Waveguide tees - E-plane tee and H-plane tee

In RF and microwave circuits, a waveguide or coaxial line junction with 3 ports is known as tee junction. This devices are mainly used for combining power and splitting power in a waveguide system.

The waveguide tees are 3 port components and are mainly of two types E-plane tee connected in series and H-plane tee connected in shunt with section or branch of main waveguide transmission line. The operations and functions of these waveguide tee types including difference between E-plane tee and H-plane tee are explained below.

### E-Plane Tee (Series Tee)

In E-plane tee, axis of the side arm is parallel to the E field, the same is shown in the figure-1.

As shown in figure, this E-plane tee type is perfectly matched using screw or capacitive or inductive windows at junction. As there is no reflection, diagonal S parameters of scattering matrix will be zero. Hence S11, S22 and S33 are zero. For matched junction, S matrix will be as depicted in the figure-1 in equation-(1).

When the waves are fed into port-3(side arm), the waves at port-1 and port-2 of collinear arms will be of same magnitude but opposite in the phase. Hence ,
S13 = -S23

Equation-(1) is for the perfectly matched junction, but in practice it will be poorly matched. S matrix when collinear arms are symmetric about the side arm is mentioned in equation-(2). Here, |S13| = |S23| and S11 = S22.

### H-Plane Tee (Shunt Tee)

In H-plane tee, axis of the side arm is parallel to the H field, the same is shown in the figure-2.

In H plane tee, when two inputs are fed into port-1 and port-2 of the arms(collinear), output at port-3 will be in phase and also additive in nature. On the other side, if input is fed at port-3, the waves get split equally into port-1 and port-2 with in-phase and will have same magnitude. These properties of H-plane tee is used in waveguide power combiner and power divider.

S matrix of H-plane tee is same as mentioned for E-plane tee. The same is mentioned equation-(1) and equation-(2) in figure-1 except here S13 = S23.

As they are poor in providing good match, tuning screw is used to adjust the reactance of the system to obtain perfect impedance match.

RF Switch basics and applications along with manufacturers of RF switch refer following link:
RF Switch

For types of waveguide viz. rectangular & circular, waveguide propagation modes, impedance matching of waveguide read following waveguide tutorial.
waveguide basics tutorial

Manufacturers of waveguide components such as waveguide to coaxial adapter, coupler, flanges, gasket, tees, termination, shorts, isolator, circulator, horn antenna, attenuator, feed-thrus, bends, loads, twists, straights, pressure windows, transformers, sliding short circuits, fixed short circuits, sliding mismatches etc. visit following link.
Waveguide components manufacturer

Rectangular waveguide dimensions as per USA standard including frequency, broad dimension and narrow dimensions, visit following link.
Waveguide dimensions table