In　this　research,　a　circular　patch　antenna　is　proposed　for　omnidirectional　measurement　of　strains.　Firstly,　the　interaction　between　the　circular　patch　antenna　and　the　strain　is　analyzed　according　to　the　cavity　theory　in　electromagnetic　waves.　The　resonant　frequency　is　determined　by　the　size　of　the　patch　antenna.　While　a　strain　is　applied,　the　dimension　of　the　patch　antenna　changes　slightly.　Then,　the　linear　relation-ship　between　the　frequency　shift　and　the　strain　is　obtained.　The　strain　sensor　based　on　circular　patch　antenna　is　fabricated　to　measure　the　strain　in　different　direction.　A　microwave　wireless　detection　system　is　established　to　detect　the　magnitude　and　direction　of　the　structural　strain.　The　experimental　result　is　in　good　agreement　with　the　strain　gauge.　It　shows　that　the　circular　patch　antenna　is　able　to　detect　the　structural　strain　omnidirectional　and　wireless,　which　lays　a　foundation　for　the　further　engineering　applications.　(C)　2020　Elsevier　B.V.　All　rights　reserved.