That's not a "combined RWJ."
You show off an antenna design, but that's common to a transmitter, receiver, and a transceiver. It's the full system that counts.
The brochure clearly describes what the system is. A solid state transmitter-receiver unit. Meaning the same unit (array LRU) performs both functions.
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You need a HPA for transmit and an LNA for receive, that's a transceiver. You can also have just the HPA for transmit without the LNA for reception. And this connects to the Vivaldi antenna. Just looking at the antenna alone will not tell you if it's a simplex, half-duplex, or full duplex.
Transmission modes include Simplex (one-way communication), Half-Duplex (two-way communication one at a time), and Full-Duplex (simultaneous two-way communication), each with distinct advantages and disadvantages.
www.geeksforgeeks.org
Simplex mode is a uni-directional communication. Half Duplex mode is a dual directional communication but one at a time. Full Duplex mode is a two-way directional communication simultaneously. In simplex mode, sender can send the data but that sender can't receive the data.
Typically all RWRs are simplex. It keeps things cheap and the TRM is always ON, meaning it's constantly receiving signals without having to turn off the receiver circuit. That's what the F-35 has in its wings and other areas.
The radar is half-duplex, but it just divides up the work required across many TRMs 'cause it has many TRMs and provides the illusion of multifunctionality. That's why big array, good; pods have small arrays, bad. So when a TRM is transmitting, its receiver channel is off. You can see how that's a disadvantage on an RWR. Now if you take a single tiny array and divide up the TRMs, you simply get a significantly less sensitive receive function with lower gain (technical term, not profit/loss), and the transmitter may not be able to match the power of the enemy signal so the jammer signal will fail.
There is a new TRM design that allows full duplex capability. But it's new and is slowly being introduced, the F-35 doesn't have it yet. This allows simultaneous transmit and receive. But the flaw here is you need a frig load of special filters and circulators in order to isolate the signal and reduce interference. It's a pain in the butt, the better option is to just use a single transmit channel but multiple receive channels, and that works a bit if you have a lot of TRMs around. Large arrays good, pods bad. The same thing follows.
Given the cost and all the associated difficulties, the easiest option is to have fully digital multiple receive channel TRMs for RWR and a separate set of digital transmit TRMs for the jammer. And this is generally co-located or separately located on an aircraft. But you don't wanna be sticking them both on a single array. That's why even Arexis comes with 2 physically separated arrays instead of a single larger array, and it must be entirely digital.
You're finally getting what I mean by allocating a set of TRMs for each role, but again you're mixing up things. There is literally no problem with interference until & unless your system is 'dumb' i.e. the computer managing the EW suite has no idea what you are transmitting and cannot tell your receivers to ignore those specific frequencies (which rapidly change over time). Separating the arrays does nothing for that purpose either.
A lot of the limitations of such an arrangement that you're thinking up actually aren't limitations at all.
Because in the end, you only have a set amount of real estate on a given airframe where you can mount anything you want.
Mounting things separately is overall a less efficient usage of available space. It's no mystery as to why we want to avoid that if the technology makes it possible to do so. If you have space for mounting 4 arrays, mounting 4 multifunction arrays is preferred to mounting 2 transmit-only & 2 receive-only arrays.
Because as far as the hardware is concerned, the combined array essentially can act as either/or, as per need. It's just vastly more efficient & vastly more capable that way. The 16-TRM can either be 8-transmit, 8-receive, or 16-transmit or 16-receive, or any number in between. There's no hardware limitation for that anymore. This can be changed on the fly, probably automatically by the system based on threat (jamming incoming AAM seeker takes precedence over updating the track of a distant emitter.). I don't know what to say if you can't see the advantage of that as opposed to a single-function array.
Additionally, going ahead we'll also be taking CCAs/net-centricity into account for this. The CCAs may or may not have a main FCR (though HAL has shown the Warrior with a radar before), but they're guaranteed to have RWR (probably even RWRJ as it saves space when adding an SPJ function) as they have to act as sensor nodes. With arrays like this, we can jam through the CCAs, while the mothership stays passive with all TRMs acting as receivers, while letting the drones do the ECM. Or vice versa, as per need. Use drones to collect data on bearing of emitters, then jam/destroy them using standoff ordnance from the mothership.
The fighter can maximize its capabilities based on the networked battlefield. You may not need to jam at all if CCAs/other fighters are in position to do that for you. Your jammer arrays are essentially wasted space in such conditions - but now you can turn them into extra RWRs that increase your ESM capability. There's literally no downside, only upside.
The multifunction array offers a lot more flexibility of operation than the single-function arrays of old. This is the approach we've chosen for Tejas Mk2 (and AMCA as well, most probably). It's a nice evolutionary improvement over what we've had before. I don't see what the big deal is.
As for your misunderstanding of the term RWJ, it's purely a DRDO marketing term. The earliest development of EW systems by DRDO came with an internally located RWR and an externally carrier pod based jammer, like the EL/L-8222. So the MKI, Mig-21, Mig-27, LCA Mk1/A, and Jaguar DARIN I/II came with Russian and Israeli pods. Mirage 2000 and Mig-29 too, but with respective foreign RWR and pod-based jammers. So this is called RWR by DRDO. And RWJ is simply an internal RWR combined with an internally mounted jammer. That's all.
Yeah well we've never implemented multifunction arrays before so that bit is new. The designation of the overall system is now called UEWS. Probably as it includes significant integration with the FCR as well (which wasn't possible on our older jets as we were dealing with multiple OEMs).
On Tejas Mk2 (and I think even Mk-1A, though it doesn't have internal jammer) the UEWS refers to the entire system as a whole - the arrays, the processing units, & the software they run which allows them all to work in conjuction.
Whereas now RWRJ is simply referring to the type & configuration of the array used to carry out the transmit/receive functions - earlier, we used to have them separately, now we're combining them.
To put it in simple terms, if UEWS is the whole TV, the 'RWRJ' I'm talking about is just the screen. I'm just saying we upgraded from an LCD to an OLED.
IN's Mig-29Ks are newly equipped with a Belarussian ECM pod called Talisman. And the Mig-29UPG comes with the D-29 RWJ, which combines a DRDO RWR with an Italian AESA jammer that's internally mounted within the aircraft.
Мираж, Амулет, Талисман
btvtinfo.blogspot.com
Basically, Mig-29UPG, Mirage 2000UPG, LCA Mk2, AMCA, and Jaguar DARIN III come with RWJs, internally-mounted ECM. Whereas Mig-29K, LCA Mk1/A, and MKI come with RWRs, they have to carry separate ECM pods. Some day Mig-29K will get an RWJ.
No, you're talking about entirely different things. I'm specifically talking about the internally-mounted 16-TRM array which reportedly can act as both RWR array & SPJ array. Not the suite as a whole. We use UEWS to describe the suite now.
Tejas Mk2 is the first IAF aircraft this will be implemented on.