IP Library › Granted Patent US 12,586,907
Granted Patent B2
US 12,586,907 · App. 18/434,427 · Granted Mar 24, 2026

Reactance-loaded sequential-phase feed network for a highly compact wideband on-chip circularly polarized antenna

Inventors: Shangcheng Kong (Kowloon, HK); Kam Man Shum (Tai Po, HK); Chi Hou Chan (Kowloon, HK)
Assignee: CITY UNIVERSITY OF HONG KONG
H01Q9/0428H01Q9/0414H01Q21/065
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Quick Facts
Patent No.
US 12,586,907
App. No.
18/434,427
Granted
Mar 24, 2026
Kind
B2
Abstract

A circularly polarized antenna that includes a plurality of radiating elements configured in a rotationally symmetric pattern, and a feed network connected to the plurality of radiating elements. Each radiating element contains a patch element, and a shorting wall connected to the patch element and adapted to short the same. Unlike traditional sequential-phase feed, which simply relies on the physical length of the delay line to achieve phase progression, the reactance-loaded feed line strategically utilizes the equivalent capacitor and inductor to shift the phase. This method eliminates the reliance on the long delay lines and realizes stable phase differences over a wide bandwidth.

Claims (29)

1 . A circularly polarized antenna, comprising:

a) a plurality of radiating elements configured in a rotationally symmetric pattern;

b) a feed network connected to the plurality of radiating elements; the feed network comprising:

i) a core portion comprising a parallel-plate capacitor; and

ii) a plurality of output arms each corresponding to one of the plurality of radiating elements; the plurality of output arms coupled to the core portion;

wherein the plurality of output arms is configured in a rotationally symmetric pattern.

2 . The circularly polarized antenna of claim 1 , wherein the core portion has a substantial square-ring shape.

3 . The circularly polarized antenna of claim 2 , wherein the core portion has unequal widths along a direction of extension of the core portion.

4 . The circularly polarized antenna of claim 1 , wherein the parallel-plate capacitor is located in front of a corresponding one of the output arms along a signal transmission path of the circularly polarized antenna.

5 . The circularly polarized antenna of claim 1 , wherein the parallel-plate capacitor comprises a first portion located in a same layer as remaining part of the core portion, as well as a second portion parallel to and located below the first portion.

6 . The circularly polarized antenna of claim 5 , wherein the output arms are in the same layer as the first portion of the parallel-plate capacitor.

7 . The circularly polarized antenna of claim 1 , comprising four said radiating elements, with a 90° input phase difference between adjacent said radiating elements; the circularly polarized antenna comprising three said parallel-plate capacitors corresponding to first three said radiating elements along a signal transmission path of the circularly polarized antenna.

8 . The circularly polarized antenna of claim 1 , wherein the core portion is fed by a feeding line that extends in a same layer as the core portion.

9 . The circularly polarized antenna of claim 8 , wherein the feeding line extends along a first direction; the core structure being shorted by a shorting line which extends along a second direction that is perpendicular to the first direction.

10 . The circularly polarized antenna of claim 9 , wherein the shorting line passes through a shorting via formed at substantially a center of the core portion, and connects to a ground layer below the feed network.

11 . The circularly polarized antenna of claim 1 , wherein each of the plurality of radiating elements comprises:

i) a patch element; and

ii) a shorting wall connected to the patch element and adapted to short the same.

12 . The circularly polarized antenna of claim 11 , further comprising a ground layer; for each said radiating element the shorting wall being positioned between a corresponding patch element and the ground layer, and connected to both the patch element and the ground layer.

13 . The circularly polarized antenna of claim 12 , wherein the shorting wall comprises a plurality of layers.

14 . The circularly polarized antenna of claim 13 , wherein the shorting wall comprises ten layers.

15 . The circularly polarized antenna of claim 11 , wherein the patch element of each said radiating elements has a substantially rectangular shape.

16 . The circularly polarized antenna of claim 15 , wherein for each said radiating element the shorting wall connects to the patch element substantially at a first side of the patch element; the feed network connected to the patch element substantially at a second side of the patch element that is opposite to the first side.

17 . The circularly polarized antenna of claim 15 , wherein for each said radiating element a projection of the shorting wall on the patch element has a substantially “T” shape; the shorting wall having a first segment connected to the patch element at a first side thereof, and a second segment perpendicular to the first segment and extending from the first segment toward a center of the patch element.

18 . The circularly polarized antenna of claim 17 , wherein each of the output arms extends along a direction substantially parallel to that of a corresponding one of the first segments.

19 . The circularly polarized antenna of claim 17 , wherein the first segment of the shorting wall has the same length as a dimension of the first side of the patch element.

20 . The circularly polarized antenna of claim 15 , wherein the patch element of each said radiating element is formed with a rectangular notch at a corner of the rectangular shape; the feed network connected to the patch element near the rectangular notch.

21 . The circularly polarized antenna of claim 15 , wherein for each said radiating element the ground layer is formed with a respective aperture that has a shape corresponding to that of the shorting wall; the aperture receiving partially the shorting wall therein.

22 . The circularly polarized antenna of claim 11 , comprising four said radiating elements, with a 90° input phase difference between adjacent said radiating elements.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Feb 7, 2024
From: KONG, SHANGCHENG; SHUM, KAM MAN; CHAN, CHI HOU
To: CITY UNIVERSITY OF HONG KONG
Reel/Frame 066411/0449 →
Continuity (1)
Related Publication 20250253534A1 · Aug 7, 2025
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