Transmission-line-based signal distribution and aggregation
A tapped transmission line for distributing an electrical signal, such as an RF signal, to multiple modules, and/or aggregating signals from multiple modules. Embodiments of the invention provide a tapped transmission line based on a transmission-line medium along which tap elements are dispersed, so that the tap elements have a predominantly capacitive loading of the transmission-line medium. Methods for compensating the loss of the transmission-line medium are presented as well. Applications for distribution of transmitted signals, of local oscillator signals, and to aggregation of signals from multiple oscillators are disclosed. The invention is particularly applicable to integrated circuits (IC, ASIC, RFIC), and to multichannel RF systems such as phased array and MIMO systems.
1. A tapped transmission line for distributing a first electrical signal to a plurality of modules, the tapped transmission line comprising
a transmission-line medium for carrying the first electrical signal;
a plurality of operational tap elements connected to the transmission-line medium at intervals along a physical length of the transmission-line medium; and
a plurality of operational negative resistance elements connected at intervals along a physical length of the transmission-line medium;
wherein:
the operational tap elements exhibit predominantly capacitive impedance to the transmission-line medium;
the operational negative resistance elements exhibit respective negative resistances; and
each module of the plurality of modules is connected to a respective operational tap element of the plurality of operational tap elements; and
wherein outputs of the plurality of modules are not connected to a common transmission-line medium.
2. The tapped transmission line of claim 1 , wherein an operational tap element is selected from a group consisting of: an amplifier, a mixer, a frequency multiplier, and a vector modulator.
3. The tapped transmission line of claim 1 , wherein the transmission-line medium is a differential transmission-line medium.
4. The tapped transmission line of claim 1 , wherein the first signal is selected from a group consisting of: a transmitted signal, and a local oscillator signal.
5. The tapped transmission line of claim 1 , wherein multiple transmission-line media distribute respective multiple electrical signals to the modules.
6. The tapped transmission line of claim 5 , wherein there are two transmission-line media and a second electrical signal is a 90-degree shifted version of the first electrical signal.
7. The tapped transmission line of claim 1 , wherein the respective negative resistances have controlled values, wherein the ends of the transmission-line medium can be short-circuited, and wherein the transmission line is testable for a presence of oscillations.
8. The tapped transmission line of claim 1 wherein the transmission-line medium is tapered.
9. The tapped transmission line of claim 1 , wherein the first electrical signal is a radio frequency (RF) signal.
10. The tapped transmission line of claim 1 , wherein an operational negative resistance element is a dedicated operational resistance element.
11. The tapped transmission line of claim 1 , wherein an operational negative resistance element is an operational tap element.
12. A tapped transmission line for aggregating an electrical signal from a plurality of modules, the transmission line comprising:
a transmission-line medium for carrying the electrical signal;
a plurality of operational tap elements connected to the transmission-line medium at intervals along a physical length of the transmission-line medium; and
a plurality of operational negative resistance elements connected at intervals along a physical length of the transmission-line medium;
wherein
the operational tap elements exhibit predominantly capacitive impedance to the transmission-line medium;
the operational negative resistance elements exhibit respective negative resistances; and
each module of the plurality of modules is connected to a respective operational tap element of the plurality of operational tap elements; and
wherein inputs of the plurality of modules are not connected to a common transmission-line medium.
13. The tapped transmission line of claim 12 wherein exactly one module produces a signal current at a time.
14. The tapped transmission line of claim 12 , wherein an end of the transmission-line medium has a signal sink, and another end of the transmission-line medium is terminated.
15. The tapped transmission line of claim 12 , wherein two ends of the transmission-line medium have signal sinks.
16. The tapped transmission line of claim 12 , wherein an operational negative resistance element is a dedicated operational resistance element.
17. The tapped transmission line of claim 12 , wherein an operational negative resistance element is an operational tap element.
18. The tapped transmission line of claim 12 , wherein the respective negative resistances have controlled values, wherein the ends of the transmission-line medium can be short-circuited, and wherein the transmission line is testable for a presence of oscillations.
19. The tapped transmission line of claim 12 , wherein the electrical signal is a radio frequency (RF) signal.