Just some brainstorming ideas from a RL EWAR expert (Its my job)

Sensors:
Make it a fitting option (new sensor slot) with different types that work differently and can be jammed differently;
RADAR: Line of sight, obscured by objects, has a maximum range, and can be jammed and spoofed (more on ECM in a moment), slightly greater detection of and by other Radar sensors. This is the default sensor. It also displays the actual minimap and not just player positions (since radar can map terrain). All Dropsuits should start with this as the basic sensor.
THERMAL: Line of sight, obscured by objects, NO MAXIMUM RANGE, can be jammed, partially spoofed. Does not display the minimap. Large explosions near by disrupts the sensor, and large explosions near a target disrupts pickup of that signature (you could hide next to a flaming wreck and a thermal sensor wouldn't pick you up well.
LIDAR: Line of sight, obscured by objects, cannot be jammed, can be spoofed, unlimited range, greatly increases your visibility to other liar sensors. Displays a detailed minimap that includes contours.
MOTION: 360 regardless of obstructions, small range, cannot be jammed, can be spoofed. Does not increase detection by other sensors at all. Displays no minimap.

Additional Sensor Possibilities:
Magnetic, best against larger chunks of metal, limited range (better than motion, less than radar) passive sensor that doesn't increase your detection by other sensors
Gravimetric, not sure how it would work well, in space its based on the sensing of gravity waves given off by starship engines, but for this game would have to be different, Im open to options.
Sound, could be just your ears, could "see" around obstacles, better detection for people shooting, sprinting, etc. Couldn't be jammed, but could be spoofed...maybe...


Electronic Warfare:
There should be two main types: Electronic Attack (EA) and Electronic Protect (EP)
Electronic Attack (EA) that consists of Jamming and Spoofing;
Jamming, an AOE or directed attack against either sensors (RADAR, LIDAR, or THERMAL) or communications (TACNET). The AOE jammer affects any sensor in range and in line of sight and prevents them from detecting.

RADAR Jamming: prevents detection of ANY thing, regardless of who is the source of the jamming. Same effect for AOE or directed.

LIDAR jamming:Cannot be jammed, only spoofed.

THERMAL jamming: prevents detection of the suit/vehicle that is jamming only.


Spoofing can be AOE only, and results in many false targets being placed on the enemies sensors.
RADAR Spoofing: adds lots of false targets in an area around the jamming source that appear to pop in and out and move randomly, actual tracks are masked as well by fading in and out.

LIDAR Spoofing: Creates false targets in a cone in the direction of the jammer source and extending out to infinity. Width of the cone should depend on the relative strength of jammer and sensor, not on position or range of the jammer.

THERMAL spoofing: Equipment module that deploys a myriad of small flares that spoof the thermal sensors in an area. Also, normal pandemonium of battle with lots of heat signatures can spoof thermal sensors.

MOTION Spoofing: Creates false targets in an area centered around the SENSOR instead of the jammer, otherwise identical to RADAR jamming, but at much shorter range.

Communications Jamming would be an AOE or directed jamming that removes anyone in its effect from RECEIVING TACNET transmissions. So data coming OUT of a jammed area would still function, but those being jammed would not receive any TACNET info. TACNET info should include the regular updates on what is being hacked or not, all of the little arrows showing enemy movements, objective orders sent VIA squad or commander commands, etc.

Electronic Protect are systems that directly counter EA systems. EP systems that are targeted at the jammer prevent that jammer from having any effect on anyone. EP AOE systems decrease the effectiveness of jammers on friendly units within its AOE.

Single Target EP systems could be modules that reduce a suit/vehicle's signature against a certain type of sensor, like radar, or lidar. Thermal masking armor, low armor points, very very low or ZERO heat signature. etc.

Vehicle mounted systems should be larger and more effective than their drop suit counterparts.

Certain drop suits should be given special roles for sensors or jammers.
For example, a scout suit should have two sensor fitting slots, a heavy should have none. A command drop suit should have bonus to fitting EP systems.
LAV's and Dropships should be able to fit more/better sensors than HAVs.
New Dropsuit designed specifically for jamming, perhaps a tech two version of scouts or assaults.

All sensors and jammers should require CPU and PG so that going full EWAR or SENSOR should cost you some combat killing power.

There would require a fairly significant amount of balancing the different AOE and targeted modules from different platforms (a targeted jammer from a dropship could be pretty effective, or perhaps dropship AOE mechanics should be in a hemisphere below the dropship.)

Jammer effect on targeted weapons like Swarm Launchers should be handled very carefully. One way to approach it would be to make any targeted weapon have some kind of tracking system that can be defeated by jamming, so one SL uses radar, then a radar jammer would make it a dumb weapon, but all other jammers would have no effect.

EMP/Electro-Magnetic Burst Weapons: Some EWAR suits and vehicles should be able to deploy AOE burst type jammers. Suits should be able to throw EMP Grenades that jam EVERY sensor type for a short period in a small area. Vehicles should be able to use a module that fires a larger EMP explosive. Dropships could have EPM "bombs" that drop straight down.