Wideband Use and Combiner Extension

The Wideband port of a Balanced Combiner allows to cascade several Balanced modules (also with Filters of different cavity sizes or different number of poles). The result is a Chain Combiner composed of n Balanced modules, having n Narrowband inputs and one Wideband input. The remaining Wideband input can be further used to extend the combiner combination capability:

Wideband Use Extended combination
Not used (Terminated with Load) 0 channels added; Future expansion possible;
Provides Constant Impedance for all channels
Single Filter 1 extra channel combined
Starpoint Combiner 2 extra channels combined
Manifold Combiner Several extra channels combined

Peak Voltage and Wideband Power

Peak Voltage Peaks
COM-TECH Balanced Combiners have been dimensioned to widely sustain the increased voltage peaks caused by the vector composition of several signals (up to 10 channels).

Wideband Input Power
COM-TECH Balanced Combiners have been dimensioned to withstand the overall output power even in Wideband mode (the Wideband input power having a double impact on hybrid couplers), thus making the calculation of the total output power extremely easy:

Maximum Output Power = Sum of NB Input Powers + Sum of WB Input Powers

Wideband Tuning Optimization

The Wideband port Return Loss can be optimized either for the best value on specific channel(s) (at the expense of reducing the performances outside the given frequencies), or to reach the best tradeoff value on the whole operating band.

Wideband Tuning Features
Channel Optimized Best values on the specified channel(s)
(reduced performances outside)
Whole-band Optimized Best tradeoff on all operating band

Combiners with MultiStep technique, available on DF Series UHF Balanced Combiners, have unparalleled Return Loss performances, allowing an almost optimal Return Loss value on all the operating band.

Insertion Loss and Return Loss on Chain Combiners

Tuning data reported on the Datasheets refer to one single Balanced module. Chain Combination requires specific calculations for the overall Insertion Loss and Return Loss:

Insertion Loss
The overall insertion loss is the sum of the Insertion Loss of the single module, increased by the sum of the Wideband Insertion Losses of the following modules:

 I.L. (Overall) = I.L. (Single Module ) + n x I.L. (Wideband)

Return Loss
The combination of several Balanced modules involves a derating of the overall Return Loss, influenced by the number of combined channels, channel order and assortment, and adjacency. For basic reference, and in case Channel-Optimized Wideband tuning, the following table is provided:

No. of Modules Overall Return Loss (VSWR)
1 26 dB (1.11)
2-5 25 dB (1.14)
6-8 24 dB (1.16)
9-10 23 dB (1.18)